easy. Depending on species. Good beginner mantis is Neogonodactylus wennrae. You can get it from Tampabaysaltwater.com for 50$ including shipping. Gets about 3" highly variable personality, but mostly outgoing. Equipment: 5-10 gallon tank. visitherm stealth heater. Glass heaters are bad because the mantis tries to kill the little light and breaks it releasing heavy metals. A powerhead or other water movement device. 5-10 pounds of rock with at least one big piece it can burrow in, and sand. Some like crushed gravel, I prefer Oolitic aragonite. If you want a quick mantis tank take a few cupfulls of sand from an established tank and some live rock from established tank and you can put the mantis in same day. i did that for my chiragra. I wouldn't advise it for sensitive species, but n. wennerae will take it fine.