Hello and welcome.
So, there's been tons written on this forum about enclosures but here's a few thoughts.
First, Tall!!! Minimum 24" to start if you are buying an Exo-T or Zoo Med product.
If you are building your own, 30" to 36" tall and you'll never need to upgrade as your Tokay grow past a foot long. And Tokay live in the vertical domain, so vertical hiding places and walls of a material that their foot pads will 'stick' to. That eliminates most plastics by the way. Glass is great. Polyurethaned/waterproofed/sealed wood will work too. And for the heavy duty, any stone especially slate is an all-time favorite of Tokay.
Using a fish tank tends to suck when you need to work on the enclosure if you are reaching in from above. Doors are a must, which allow side access without disturbing them. Remember predators come from above and will stress your Tokay into fight or flight when you reach in from above.
Ventilation is a must, so a screen top and some side venting would be good. You will be creating a very wet environment at 90+ degree temps which can breed trouble without good air flow.
As to your Tokay pricing question, here's a general ballpark:
Wild caught normals $15 to $25, plus the $125 reptile vet visit and fecal exam and internal parasite meds. (If you skip this part you have about a 10% chance of the poor guy making it, just read all the "HELP, sick Tokay" threads.)
Normal captive hatched, $40 to $50. This is when a gravid import drops eggs and they sell the un-sexed hatchling.
Normal Captive Bred, $80 to $125. These are domestically bred normal type Tokay that are usually old enough to sex, so they are around 8 months old.
Long term captives, treated and acclimated imports, $80 to $125. These are well established wild caught Tokay that should be free of parasites, eating well and healthy.
Morphs: $150 to $3,500. Typically 'fancy's, some of the patternless olives and greens will start around $150. Patternless powder blues and powder greens can range from $300 to $500.
Granite, Melanistic and lower grade Calico $500 to $750.
Better Calico, Leucistic and Caramel Albino, $1,250 to $1,850.
True Pied, $2,500, Super Reds, $3,500.
Obviously these are subject to market demand and availability and other factors. But just as a ballpark, this should get you close, enjoy.
Michael's Tokay Hoard @
www.billewicz.com