There's a $1 per gallon sale nearby so I was considering getting a 5 gallon aquarium and buying a ZooMed 501 canister because it's half off too.
I'm also considering getting a 3L bag of ADA amazonia aqua soil and maybe the power sand special - S (still not entirely sure of the benefit of the power sand).
5 gallon being 16" long and 8" width, would this be enough substrate to cover the bottom?
Lighting is where I don't know what to get, I'm thinking about maybe getting a finnex fugeray planted + unless I can find something that looks just as good for cheaper.
Does anyone have any advice or can point me towards anything else?
A 5.5 would be fine. I'm thinking of either doing the ADA power sand/ aquasoil, or taking some of the flourite and eco complete from my other two tanks and placing that on the bottom and then covering that bottom layer with some CaribSea super naturals moonlight or sunset gold sand, then placing some osmocote capsules in to make up for the lack of nutrients.
I did along the same lines of what your thinking today. Went to Petco and bought a ZooMed 501 for half off ($27.49). I've used this filter on my 12L and 20L and am a big fan of it, especially for $27.49! I've had one of the new Fluval Nano LED's kicking around for a little while as the tank I got it for was to large (10g!). FYI the new Fluval Nano light is on sale for $80 from $90 but I can't say I recommend it yet. Put it on my 10g and half was fairly dark. After experimenting on several tanks with this light I've concluded it's around medium light on a 12" x 12" x 12" and high on an 9" x 9" x 9". I plan on picking up a Mr Aqua 5.2g which is 10" x 10" x 12". Using some Ativ-Flora Planted Substrate (highly recomend) from my 12 long and an old Ista 45g Co2 system lying around.
For you I would say a 5g would be a good size and you'll get TONS of flow with that filter so be sure to pack extra media in there to slow it down a little. As for light on a 5g I've never used them but seem amazing results with the finnex. Best of luck!