Yes, heating your pool can be practical. It's just the method that can be a pain in the back or wallet.
Solar panels can be had for $100-150 for a 4x20. You would need 50-75% of your pool surface area to be effective.
Natural gas, depending on your local price per therm (thousand BTU), can be the next least expensive, with propane running a bit higher.
If you have a source of free wood, and are willing/able to apply sweat equity can be an option. The commercially made units are a bit pricey. Note: I built one. Not very efficient, but gets the job done.
For your pool and location, a 100,000 BTU/hr unit would work, I think. Unless you are wanting to try to keep the pool open year round.
Others will probably weigh in on this. Good luck!