I'm in the same position as you, and what I do is treat it like a game where the challenge is to take $100 and see how far I can go with it, and keep within the limits I set. MTT's can be difficult for a small BR though because the paydays are bigger but the time inbetween those cashings can be longer. How I compensated was to play SNG's until I had enough extra to pay for a MTT buy-in, rinse and repeat.
Or you can treat it like entertainment dollars. Budget how much you want to spend on entertainment and stick to the budget. If you have $100 a week to spend on entertainment, be it dinners or a sporting event, factor in the poker $ and reduce spending elsewhere.
The important thing is to decide on a budget plan, stick to it, and be honest with yourself. I've been playing for a few months now, and to be honest, I'm up a total of about $2. Thats tough to admit seeing as at one point I was up $160.