Click "View more info" for useful links, including my trade offer link:

My trade offer link
http://steamcommunity.com/tradeoffer/new/?partner=164314492&token=W9uGoi6j

TF2 trading forum
http://steamcommunity.com/app/440/tradingforum/

CS:GO trading forum
http://steamcommunity.com/app/730/tradingforum/

Cheapest games in the Steam store
http://store.steampowered.com/search/?sort_by=Price&sort_order=ASC&price=0%2C5

Cheapest TF2 unusuals
http://steamcommunity.com/market/search?q=&category_440_Type%5B%5D=any&category_440_Quality%5B%5D=tag_rarity4&appid=440#p1_price_asc

Cheapest CS:GO knives
http://steamcommunity.com/market/search?q=&category_730_ItemSet%5B%5D=any&category_730_TournamentTeam%5B%5D=any&category_730_Weapon%5B%5D=any&category_730_Quality%5B%5D=tag_unusual&appid=730#p1_price_asc

Create a guide for Steam not tied to any particular game
http://steamcommunity.com/sharedfiles/editguide/?appid=753

Card list, emoticon list, item value sorter
http://steam.tools/ (not an official Steam site)

Funtrivia.com , with lots of quizzes on all topics (including several on Steam games)
http://www.funtrivia.com/?ref=hotdogPi

Do not click:
https://www.youtube.com/watch?v=dQw4w9WgXcQ