Tubeless isn't a very expensive investment and worth it. Depending on the wheels/tires you have it can be as cheap as $20, I wouldn't expect it to be over $50 with labor if you needed rim tape or other things.

Like others have said the whole point is the sealant seals the hole and you can keep riding. Sometimes I have had ones I have to "help" seal. You turn the tire where the hole is at the bottom and wait for it to seal. Maybe add a little bit of air. Sometimes you don't even realize you have punctured because it seals that quickly. And then there is the dreaded third scenario where you have to put a tube, dreaded because who wants to change a flat on the trail?

I like 29er, hardtail or FS but I say ride both and decide.