There are some resale places around here (Play-it-Again sports) that re-sell equipment, maybe there's a place like that too around you.
The most importnant thing is to buy something that you'll USE.
Start with some new shoes and clothes, and 'reward' yourself with new equipment as you stay on track. That's sort of how I got such nice stuff...I used my old stuff until I was convinced that it was worth spending the big $$s on nice stuff. The bonus on dropping serious coin, is that I feel too guilty about spending the money to let it sit there collecting dust
Works both ways. It'll be quite awhile before I make up what I would have spent on gym memberships, but it's harder to talk myself out of a workout when it's in my basement vs. across town...