For an enclosure of that standard size, I don't think you can save much money and make an enclosure anywhere near the quality of something you can buy from LLL Reptiles or DIY. Building your own makes more sense with larger or highly custom enclosures. I would recommend buying one - heck of a lot easier on you. For basking spots, you can hang vines or branches about 6-8" from the basking lamp where the temperature hits the mid-to-low 80sF.
You should check out the enclosure stickies for ideas on how to organize and decorate your cage:
https://www.chameleonforums.com/official-enclosure-picture-thread-49688/
https://www.chameleonforums.com/official-enclosure-picture-thread-2-post-your-pics-94781/
For plants, most people will recommend: golden pothos, umbrella plants (schleffera), ficus benjamina, and crotons. All three are indoor plants that are pretty easy to keep and should be readily available from any big hardware or garden store. Chams also love hibiscus trees, but they can be fussy and hard to keep if you aren't a plant person. Pothos are super easy and make vines the perfect size for Jackson's. My Jax loves the vines and huge leaves of my pothos tower.
There is a long list of safe plants for chams, just be aware than many household plants are not on the safe list:
https://www.chameleonforums.com/live-plant-database-2632/
You can make your own dripper from a bottle, but making your own timer and mister or fogger will be much more difficult. I have a MistKing system. It cost about $100, but it was worth every penny in my opinion. It works great and their customer service is tops. Look into the MistKing and AquaZamp (I think) misters. Jax need high humidity and my guy just loves lots of water.
Make sure your lights (basking and UV), supplements, feeders, humidity, and temperature are all in place, and you should be ready to go.
If you haven't read through this already, here is a fantastic resource:
https://www.chameleonforums.com/care/caresheets/jacksons/
Have fun and post lots of pictures!
