I have been using a used Shimano Dura-Ace crankset since I got my bike. Initially the crank set was put on incorrectly, and one side of the teeth dug into the other side, and now the arms can move about 1/4 an inch independently. I had a friend put it all together for me (he did a great job) but now I am to the point where I need a new crank. How do I go about determining what I need? And, does anyone have any suggestions.

Specs:
Shimano Dura Ace FC-7701 (175)
Larger ring: SG B 53
Smaller ring: SG B 39
Back: 9 speed, 12-23

Should also note, I dont want to spend that much money. $100 max.

Thanks everyone.

I guess the question is if the bottom bracket, crank arms or both are damaged. You will have to take it apart and inspect it. To find replacement parts in your price range, E-Bay might be your best bet.

Been searching for parts to put a whole bike together, not sure of the condition of the crank arms, but it sounds like you might be able to get away with a new double chain ring set (shouldn't be more than $30-40 likely can be bought at your LBS) and a Bottom Bracket, which can be had on ebay for between $10-$60 on ebay (luck of the draw and whether you go with Dura ace, ultegra, or another brand that is Shimano compatible, and has the correct threads for your bike). If you need the crankset and BB, you can likely get a good deal on a package set, or buy them individually.....not sure if you can find a new dura ace and BB for $100, but an ultegra should not be an issue at all, BIN's on ebay for those are about $75 w/shipping

not to hjack your tread but do all crank arms bolt on the same? I want to change from 172.5 to 175mm but don't see any reason to change chain rings and bottom bracket etc..

not to hjack your tread but do all crank arms bolt on the same? I want to change from 172.5 to 175mm but don't see any reason to change chain rings and bottom bracket etc..

no, they don't all bolt on the same.
but if you're going from the same type and only changing the size you'll be fine.