Hello Alexander. Welcome to the Forum. I'll throw in my two bits worth.
First, the plane you are considering is still (at $23,000) priced way too high. As Gremlin indicated, $20,000 is tops. There are more than a hand full of C150's available at any time in any region of the country, and there is nothing special about this one.
Secondly, the cost for an owner to fly his/her C150 is a minimum of $50/hour (low, not really taking all costs into account) to $100/hour depending on hanger, flight hours/year, any major repairs. You have not wasted $500 on renting. You have had the use of the plane, and then you got to walk away. No paying for inspections, repairs, insurance, tie-down/hanger, engine overhaul fund, etc.
Enjoy flying, and for right now, enjoy renting. Your cost per hour is not that far off of owning. As you gain more experience, you will better know what you want/need in a plane, and the more patient you will become about finding the right one at the right price.
Mike.
