That sounds awesome! Veileds are among the most forgiving species, and certainly a great place to start. They are a large species, so the bigger the enclosure, the better.
Cage size: MINIMUM cage size recommended is (LxWxH) 2x2x4, or 2x3x3. The former size is most often found in screen cages; the latter in glass. But again, these are minimums, and there is no harm (and tons of benefit) to going larger and/or building your own.
Cage material: It seems like both screen and glass with work for you. Without knowing your humidity levels, I don’t know how much work you’ll have to put in to tweak things, but one question to ask yourself is how your house is heated. Forced-air, gas-fired furnaces dry the air; radiant heat, less so. Just a consideration to keep in mind. Screen enclosures have the following attributes:
Pros
- lighter/easier to move around
- cheaper
- easier to keep cooler
- provide the best amount of air flow
Cons
- make mainting high night time humidity challenging
- make containing water from misters and dripper more challenging
- admit of more feeder escapees
- structurally weak
Glass enclosures:
Pros:
- structurally strong compared to screen
- makes keeping nighttime humidity high a breeze
- fewer escapee bugs
- generally offer more insulation from environmental temp/humidity swings
- good at keeping water in
Cons:
- heavy
- can present a challenge for day time humidity drops (esp. if substrate is used)
- can heat up and retain heat from basking lamp
- expensive
- too good at keeping water in
Bio-active or not?
This is personal choice, as it comes with its own benefits and challenges. I’ll let somebody better versed in bioactivity chime in here. What I can add is that I’d hold off on going bio active until you get a couple clean fecals. Thebread on being that if, by chance, your Cham comes in with pinworm, or some other parasite, you’ll end up having to tear down the bioactive environment and start over during treatment. So, just wait a month or so before adding substrate or going bioactive, so you can make sure your not introducing a plethora of extra hiding places for parasite eggs.
humidity:
This is a hot topic right now, so I’ll try to be as non-partisan as I can. Almost everyone agrees that lower daytime humidity (as low as 30-40% for veileds) is good, and higher nighttime humidity (>90%) is also good. But there is a ton of contention about how to achieve that: should we fog at night, mist, or just have a sufficient number of plants in hopes of achieving this...or some combination thereof. I will try to be as non-partisan as I can here. Daytime humidity specs are easy to achieve with a screen enclosure, as most of our homes fall in the 40 - 50% range. Glass can be more difficult here, but tons of keepers manage it without too much hassle, as glass enclosures always have a screen top and venting in front. It's the nighttime specs that become more complicated. With screen, most people find they have to use some sort of shower curtain system to cover several sides of the cage; with glass things are simpler. The reasons proffered for high nighttime humidity are as follows:
1. It replicates what happens in the wild (this is uncontested)
2. chameleons lose less water through respiration if they're breathing in humid air over night (this one has been hotly contested, with decent arguments and evidence on both sides)
What ever method you decide on to raise nighttime humidity, make sure to incorporate it in such a way that any requisite maintenance on the humidity system can be carried out easily--this is especially true if you decide to use a fogger!
hydration:
While this is tied in heavily with humidity, it warrants a separate section. Chameleons do not typically recognize bowls as sources of water. They mainly drink droplets/condensation off of leaves. So a daytime dripper is a great idea. Some people elect to mist during the day too, but too much day time misting makes it difficult to hi your daytime humidity specs. What I do is mist for 3-4 minutes just before lights on, so my chams can wake up to morning dew and drink, then use a dripper during the day, then mist just after lights out. If things get really dry during the day, I'll add a short (20 sec.) mist in the afternoon.
Heat:
Veiled specs are thus:
Daytime ambient: 72 - 76
Daytime Basking: 82 - 88 (some people recommend the low side for females to reduce clutch size...but that can come later)
Nighttime ambient: 55 - 69
Lighting:
A good T5 high output linear fluorescent bulb is a must (i.d get a 10.0 or 12%), as is an additional plant growth T5 bulb if you plan to grow live plats indoors without natural light. Since you mention budget is not a huge concern, start off with buying a SOLAR METER 6.5. This will really help you set things up properly in your enclosure. You'll also need a moderately low wattage basking lamp.
Set-up:
1. A number of horizontal perching branches running across the top 2/3 of the enclosure with the highest place right under the uvb and basking bulbs and receiving 3 - 6 UVI (as per your solar meter 6.5), and a basking temp of 82-88. 2. A densely planted middle section whether your chameleon can hide, escape the heat, and sleep. 3. the bottom area that can be planted (if you go bio active and use a substrate), or clear of obstructions so you can do your housekeeping.
There's a ton more to say, but this should get you started.
and welcome !!! 
