If you can afford it, you enjoyed yourself, and felt you got your money's worth, then who are the rest of us to tell you "you spent too much"
That said, yes "you paid too much" but who gives a fuck? lol
To give you some context, I also live in a small town, barely 100,000, but also with a decent sized college. Over the last 18 months or so I have seen several dozen young ladies, most of them young cute college girls like the one you were just with. The MOST I have paid out of about the 50 or so different SB's I have been with has been $500, I have paid that much maybe a half a dozen different times, but every one of those times was for an overnight date. The most I have paid for a non overnight date was $400 and that was for a date that lasted about 5 hours. Most of my dates have been around half those rates, with my "average" overnight date running about $300 and my "average" multi hour date running about $200.
Yesterday, I too had a "first date" with a POT SB. 25 years old, non college student, really cute, about 5' 1" and maybe 100 lbs, We were going to meet for drinks, but she came right over to my house instead, we had a couple of shots of tequila, had a regular drink and chatted for a bit, then I leaned over for a kiss and it was off to the races. Money was NEVER discussed. She had to go after a couple of hours to meet her mother and sister for a late lunch early dinner (yes we were drinking tequila in the middle of the afternoon. lol) so I gave her a hundred bucks to be able to pick up the check and she was thrilled to death.
My point is that I think some of you guys are doing yourselves a disservice by doing all this "negotiation" about allowance prior to hopping in bed with your POT SB's. Yes, you are going to have to pay 99% of the time, Ok more like 90% of the time for me as I have had a few SB's who NEVER asked to be paid and a couple who I am sure would have been insulted if I even offered an exchange of "money for sex", but those are the exceptions, not the rule.
My advice is that if you believe you really did give her "O's" is that you renegotiate your deal with her in exchange for seeing her regularly, If she really is a "non pro" and she really does like you even a little bit, there is no other way she is going to pick up an extra grand a month for a few hours of "work" each week. At $12.50 hr, she'd have to work five hours a day, four days a week to make that much, even more when you consider taxes.
BTW, I don't believe in "Unicorns" I do believe there are countless thousands of young women who would love the chance to double or triple their income by spending a few hours of "quality time" with an older guy with a few bucks to spare. To call them unicorns makes it seem like they are few and far between, and I simply don't believe that is true. Once again to put things in context, for the same $500, I can probably get laid every day for a week in an environment similar to yours. Now if I were in a big city, especially one like LA or NYC, my expectations would be completely unrealistic and you probably are paying right at "market rates", but in a small college town your money can go a long ways if you aren't too repulsive to be around. lol