research who is doing the work
don't always go with the "best" price
if the job would normally run 100$, and someone is offering it to you for 20, you might want to be careful ;)

actually, most of the "good money" paid requests i've read are more like the opposite... people think a job worth 10$ when it's so complicated to code it would worth 1000$, so nobody answer it.

I use rentacoder.com as well; as a coder i'd rather loose 10% of my income (esp as i can just charge the client more) than loose it all if they don't pay.

I have Paid ForumsMods For My Plugin to Update it And i Paid him 62/100$ but he haven't replied me:(

i have Sent him many PM's in here and on ForumsMods.com
Please Ask him to Refund my Money:(

if you have payed by PayPal open a dispute with them...