You're asking for a lot....... Good luck finding any for sale, and even more good luck finding any for sale for $20. Slings have been selling for more than that!
You are also going to have a lot of trouble maintaining the correct humidity for this species without a lid on the tank. And, yes, scorpions can't climb smooth, clean glass, but they certainly can climb out of un-lidded glass tanks with the aid of the silicone in the corners. They'll also obligingly make use of any chips, scratches and dirt on the surface of the glass to break for freedom. Don't underestimate their climbing abilities.