You've gotten some great advice so far! I have had my imbellis community tank of 6 for about a month now and I just love them!
I got mine from Anthony at Wet Spot Tropical Fish in Portland. They do have an Aquabid account, it's called Wetspot. You can contact Anthony directly at firstname.lastname@example.org
I have ordered 3 different wild species from the Wet Spot, they're all very healthy and happy fish, none aggressive and no signs of splenden interbreeding. They also ship with high quality materials and include heat packs or cold packs if needed.
Tony at the MN Betta Shop is also fantastic, I'd recommend sending him an email before you stop by so he knows to have his wilds out on display. He does usually have a couple of pairs out but I'm sure he has more, and he tailors his retail display based on customer needs. You can even set up a private appointment with him. He carries some harder to find products and live foods as well, so be sure to inquire about those. The only reason I ended up going with Wet Spot over MN Betta Shop for the wilds was pricing, but both are very knowledgeable sources of healthy fish.
I think Arcade Street actually has 3 betta shops :P
I feed my wilds a mix of .5mm NLS pellets, frozen brine shrimp and blood worms, live grindal worms and soon will be adding live blackworms to their diet. I will also give them live mosquito larvae once winter is over.
If you're interested in doing a community tank, I LOVE the 20gal Long Aqueon tanks. They are perfect for bettas because they have lots of horizontal space to swim around in without being too tall. Even better, you can grab them for $20 each at Petco's $1/gallon sale (which I believe is still currently going on?) I pair that with a Versa-Top 30 cover (I buy these online on Amazon, they're WAY cheaper online!). It's very important
that you have a covered tank for wilds, they are great jumpers. I tape the sides of the covers down with shipping tape to ensure not a single seam or crack is exposed for anyone to jump out of, after hearing horror stories from LBF and Aus. The upside to being so careful about this is that the humidity level in the tanks remains higher than the outside air, which is good for the fish and means less water evaporates from the tank. I have done all NPT tanks for the wilds to encourage plant growth, I use Miracle Gro Organic Potting Mix (with the sticks removed), capped with either Quikrete's Fine Grain or Play Sand. The Fine Grain is easier to work with IMO, as it does not need to be pre-washed and it settles down fast. The Play Sand needs to be rinsed 10 times and will still kick up dust for a couple of days.
Now, if you're more interested in breeding up lots of fry, I would advise that you go a slightly different route than me and go with one pair in a 10 gal (or slightly smaller works too, space constraints for wilds are more of a suggestion than a rule), and a bare tank bottom. You'll still need plenty of plant cover so they feel secure.