Broderickgil,
It's not just a matter of supplies. A vivarium needs to be constructed in a proper manner, otherwise you'll get problems with dying plants, mold, bad smell, etc. I suggest to dedicate a few weeks to reading up on the subject. Study how others have built their vivariums and learn from that. A good place to start is the "Parts & Construction" forum at Dendroboard (
http://www.dendroboard.com/forum/parts-construction/). Skip everything that deals with waterfalls or water features though, you don't want your mantis to drown. I also suggest that you stick to hand spraying for this first construction, it makes things less complicated.
Most of the supplies you need are available in aquarium shops and stores that sell flowers and garden supplies. First of all you need a suitable container. An aquarium or terrarium would do nicely. The lighting can be bought in an aquarium shop. It will be expensive, quite possibly more expensive than the aquarium or terrarium itself, but it's a good investment. Without sufficient lighting, the vivarium will look dull and the plants will lack luster, or even die outright. After that, the rest is relatively cheap. A layer of LECA/hydroton to cover the bottom 1-2 inches, then a layer of mosquito web (or something similar) to prevent the substrate from mixing with the bottom layer. On top of that, a mixture of bark chips (without fertilizer or other additives), coco fibres and peat moss. A commercial orchid substrate mix will most likely do just fine, but make sure it doesn't have any fertilizer or other chemicals added.
You may also need something to get access to the bottom layer in case you need to drain water. I use the top of a plastic bottle for that, like this;
It's hidden under a layer of moss but easily accessible whenever I need it. One of the most important things to understand is that the substrate should NEVER be in direct contact with the excess water. That's what the LECA/Hydroton layer is intended to prevent. If that happens, nasty bacteria will start to multiply and the vivarium will smell bad. The plants may also die. So, make sure you have some way to drain water from the bottom layer.
You ought to introduce yourself on the Introduction section, btw. 
