No Rush, spend some time on forum and get to know more about domain names,and if You really want to buy as soon as possible then add little bit more to your request what is your developemnt plan + your budget...
If you're interested in three letter .com domains, with $80 you can still get L-L-L.com domains for reg fee. There are about 5,000 still available. With your budget you could get around 10 of them. Some examples of what I mean are B-N-C.com or H-A-N.com
I saw another thread somewhere that showed 100's of L-L-L.com developped websites for companies, so they are being used and do have value.
Aren't any left with all premium letters though, so the remaining ones will have at least one X, Z, Y, Q, V, J, U, W etc. which aren't so bad in the right place.
You might be able to get a L-L-L.com with premium letters for $80 from someone here though, haven't seen anyone try yet. good luck!