Drew,

Used DB's in good condition maintain excellent resale value, so you can't make too big of a mistake there.
Don't buy new unless you know exactly what you want and why.
Never finance (OK, I threw that one in at no charge. )

When it comes to buying used, consider these things:

Rule #1 Buy the one with the best trailer.

Rule #2 Buy either Tin or Glass.

Rule #3 Pass on Wood.

Rule #4 Buy the one with the most blood stains.

In the meantime, keep ho'ing rides cause you're going to need the practice for when it comes to ho'ing turnarounds.