Топилцата or “the Smelter” is the peoples answer to the city of spa hotels.
While you can spend big bucks on a nice spa hotel visit in Velingrad, but there are several more affordable public baths in town: Sulphur bath, Veliova bath, Flint bath, Mud bath, Radon bath and the open air Yosif Schniter and Kaferinova pools to choose from. Also the Thermal Camping offers 3 outdoor and one indoor pool and saunas for 20lv/day if your not camping there anyhow.
If you are still in search for the free outdoor experience: Walk right past the radon bath house for men and you will find 3 outdoor pools in the fenced area and 3 more rock pools at the river bank at your disposal. Radon levels seem to be rather tame: I could not detect much gamma radiation above background levels.
Topiltsata, Velingrad, Bulgaria: Maybe the low key environment makes this not the most conducive of options in Velingrad. Solid option nonetheless. – bert