Once again my organizational skills come into play here as well. A lot of my races ran are small, local races with minimal fees ($20 range) and I even had a few complimentary entries and even won a few. I carefully map out when I am going to register for races based on payday schedule, price increases, and coupon codes (I am all about saving money when possible). Yes, I had a few splurge races (Rock 'n' Roll Vegas, runDisney races, etc), but for the most part a lot of the races that I run are fairly inexpensive and cost less than one some people spend on a few cocktails on the weekend. We all have our things that we like to do on the weekend - racing is mine.
In all honesty, it has just come my norm. I start most Saturday morning with an early morning wake up call, get my run in, have some breakfast, come home and shower and start the rest of my day by mid-morning.