I like doing laps every other day, Is there a lap pool that's not a 200 baht rip-off per day anywhere?

Cant think of any public swimming places besides the beach. Some hotels have fitness centres inc pool access you can join by the month/year. It'll work out much cheaper.

In the village (Mu Ban Chom Thong) near N 7.858910°,E 98.350304° you will find a swimming school with a reasonable pool. Admission is just a few Baht, maybe you will be limited to two lanes while a school class is getting lessons. Well worth a try. Feed the coordinates in your Navi or Google Maps. In Patong I would have a look at Aroonsom, Andaman Beach Suites, they got a nice pool, too.