Recluses, and the genus this hobby argues about most.
The venom is cytotoxic and a minority of bites produce necrotic lesions requiring medical attention. The frequency of that outcome is genuinely disputed in the literature and the popular understanding overstates it, but overstated is not the same as false. They are also small, cryptic, fast, and capable of surviving in a house indefinitely if they get out.
Legally restricted in various places and ethically contested within the hobby itself. Prices are near zero because they breed readily and demand is limited. If you are considering this genus, the question is not cost, it is whether your enclosure discipline is genuinely good enough.