Yeah $50.00 for a good lock is no big. I have no problem spending money on a good bike lock and a safe helmet (I know that $40.00 can buy you a good one these days, so no big). When the bike is only $40.00, you can afford to pay for your yearly tune-up and such. For me, commuting isn't just cheaper for work, but also going to get groceries and the like. I have supermarkets on a few blocks from the apartment I am leasing and this will mean I can go pick up things quickly. If I spend $250.00 total, I can recoup that. If I spend $500.00 total (buy a $200-$250.00 bike) it's not going to save me money.