The backpack page doesn't tell you the number of items or max number of slots

What's the difference between asking for quicksale unusuals, and selling weapons for a bud? Both are blatant disregards for item value in the hopes of making money.

Maybe it's because the post is hidden

SourceOP forums
TF2 item buying/selling
Find someone with a [WTS] thread (mean's Want To Sell / Willing To Sell / whatever)
Make sure they have:
1. a clean Steamrep page - not a marked scammer, not even a caution
2. They have plenty of SourceOP rep involving real money trades
SourceOP only allows reputation if the transaction is done on SourceOP. Outpost or TF2TP are not valid proof of transactions, so it's safer.

And what Champelliot said, send the money through Paypal. Some/most traders will also require you to have a verified Paypal account too.