It depends on what size you get it as and what type. If you get it as a sling, the smaller the better. I had my versi in a small vial (arboreal), it's only about 4-5 inches long.



I have my larger mexican red knee (terrestrial) in a carry home container (like the ones you get from expos). It's about 6" x 8" if I had to guess, I just poked some holes in the sides and top for ventillation.


I also just recently found these acrylic boxes from Michaels craft stores, in 3 different sizes, I soldered holes in the sides and top. I just used a metal hanger heated up on my stove. This one is 4" x 3" x 3" I believe...my greenbottle blue is in it (semi-arboreal)


As for substrate, I use either coco fiber or unfertilized potting soil. Terrestrial spiders get deeper substrate, arboreal spider get less

Good luck! I suggest handling a few before you make a solid decision.