I have a ten gallon glass I'll go through my cost for you, assuming you only have that
Top: ten bucks
Locks:idk i use heavy rocks, always worked for me
reptibark 15 bucks
heat pad: 15
Dimmer or thermostat:well my dimmer which the uth is hooked into cost me 8 bucks to make (and ill upgrade to a thermostat once i get more money)...but this will vary greatly, and I wouldn't recommend the dimmer route, its just unexpected car troubles forced me to for now
Hygrometer: 13 bucks
Coconut fibers 2 bucks
Water dish 4 bucks
Insulation for outside three sides...idk don't use it, but thats only bc I use a ceramic heater (as well as the uth) in lamp w/ built in dimmer control and the dimmer lamp would cost 15-20 the ceramic would be 25-35 I would think, but I do it bc i got it at a show for 5 bucks.
background for three sides to enclose it to make snake secure...however much depending on what you use
4 layers Aluminum foil on screen top cover 3/4 it...i just had laying around
My hides...1 buck, but plan on geting new heavier ones at next show so 15
Also, add in your decorations if you want

All this gets me good readings, keep in mind w/glass your going to be losing alot of heat, so don't be surprised if people recommend you a tub instead.