Ropes and chains
There are a multitude of ropes, chains, locks, rims, and so on. I'd probably be awarded with a ph.D, if I described every BDSM-item in detail, so I'll stick to a few good items, which I know works every time ! -and a few examples of what not to use...

Rope come in all different types and styles. Most will probably know the blue nylon rope, which is a good rope for towing your car - but in a bondage context it's no good, as it's got a raw and hard surface.
My pick of choice is a "Roblon standard skøde". It is a brilliant bondage rope, as it's got a pleasant ( almost cotton like ) surface, and a reliable strength. You can buy it in most DIY centers, as well as any ship's chandlery. It comes in red, white, yellow, green, blue and some places in black.

"Climbing rope" can be purchased in most well equipped sport shops. It is a little harder to bind, as the surface is a little slippery, but with a little practice it's good for bondage anyhow. It is most often neon-colored.

The thickness is of importance too. First of all the rope must be strong enough to carry the strain you apply to it, and then again, it must be thin enough, to let you tie a knot with it. My personal opinion is, that a thickness of 6 millimeter is the best, but that's a strictly personal opinion. Others will swear to 8 or 10 millimeter.
If you're a complete beginner, I'd recommend that you buy 3 pieces of rope, i.e. 2½ meter length, one in 6mm, one in 8mm, and one in 10mm...

Chains are a brilliant invention, but they've got their backsides as well. One is that they've got more or less 'rough edges'. You might find chains with a nice polished surface, but in my opinion, you'll need some experience, prior to playing with chains & padlocks !

The tensile strength is a most important issue, especially if you're getting into suspensions, and you are strongly encouraged to ask whenever you're buying ropes.
However, it's possible to test the tensile strength yourself, and it's a good idea to do it every once in a while, as rope suffers from tear and wear...

The method goes like this:
Tie one end of the rope to a stable point some 2-3 meters above ground/floor.
Tie a good stick to the rope app. ½ meter above ground/floor.
Let your partner sit ( carefully ) down, on the stick. ( Like a swing )
If the rope stands the strain, let your partner jump a little up and down. 
If the rope continues to take the strain, then let your partner climb up, so that your partner is standing with her feet on the stick.
If the rope still carries the load without problems, let your partner jump up and down, increasingly powerful.
If the rope hasn't started to break apart/rip yet, it's safe to use for bondage..!


The same test applies to chains, rims and so on. 

Please remember, that if your ropes break in a scene, your partner will most probably get seriously injured, as he/she will fall like a rock !

In case you've got a foam rubber mattress, the right place to put it while testing equipment like this, is under the rope ( of course ).

'Other stuff that can be used':

There's no end to what you can see pictures of being used for bondage around the web, and I've found 1½ thing, that can be useful. The first one is a brilliant invention, the other one is somewhat questionable.

1/ Cling wrap; is an alternative way of bondage, which has it's obvious advantages. It is (almost) transparent, it 'sticks to itself' which means that tying knots is not necessary. 
However, there's 3 things with this that you'll need to keep an eye out for. a/ You may need a pair of good scissors (with blunt ends), in order to free your partner. b/ It's got an ability to insulate the person cling wrapped, meaning that if you use it for a 'long time bondage', you'll need to be aware of the fact, that it'll be necessary to replenish the liquid lost through sweating. c/ It's absolutely air-tight, which means that you cannot cover nose and mouth with it, as this will ultimately kill your partner.

Bondage tape; is in reality Cling wrap, only a little thicker, and cut into rolls, which are not as wide, as the usual cling wrap, (an usually either red or black). It's a perfect solution, if you'd like to play with this kind of bondage, but it cost half a mountain n the 'porn community'. It's possible to buy it from 3M, just under a different name, and only in whole-sale. The 3M ID-numbers are 8884 for a thickness of 130 my, and 8886 for a thickness of 150 my.
If you know somebody, who can buy wholesale products, I'd like to know about it.

2/ Gaffatape (Duct tape); Is sometimes seen i.e. used for gags, and seen in a narrow context it works fine, as it's stopping any comments from your partner. However, there's one disadvantage, simply that I expect you to be using your masochist again, and it's reported, that it'll tear the skin from the body, when removed. One solution to this problem, is to use a good layer of lipstick, if you're using it to gag your partner, and/or to apply a layer of cling wrap to the skin, before applying the duct tape.
If you're using it to secure i.e. arms or legs, another disadvantage can be, that the duct tape may remove any paint, from the object(s) you tape your partner to. I've got no personal experience in this matter, in a bondage context, but I think, that the disadvantages outlined should be stated, in order to let you know, what you're getting into if you're fond of this kind of bondage.

A few words on things that does not work, in bondage: The list of things, which will not 'perform safely' in a bondage context is virtually endless, but here I'll give you a few hints, on things, which will not work, and tell you why - in order to supply a way of discerning if your special request will be good or bad.

Electric cords / Jump ropes / plastic covered cloth-lines: The problem with these is, that their surface makes it virtually impossible, to untie a knot. Especially if the sub has been 'fighting it'.

Cable strips: You'll probably have seen the police use a kind of cable strips, as a sort of 'disposable handcuffs' in connection to i.e. large demonstrations or someplace like this, but they are not good for bondage.
One reason is, that they might 'tighten up' during a session, which may get very unpleasant, and in the end, dangerous, as they might cut off the blood circulation.
Another problem, at least with those available in 'open trade', is, that they've got sharp edges. In my opinion this is bad BDSM.

As previously mentioned, the list of no-good items are virtually endless, but I hope, that this will give you some hints to what to look for, prior to finding out that some idea ends with a disaster..*S*
There are people, who use duct tape for bondage, knowing that it will rip off the skin, and just regards this, as 'part of the game' - and they're absolutely welcome to do so, but they should nevertheless know what they're getting into.