Filtration:
Can go for a HOB filter like AquaClear. I have AC30 myself on the 10g and it works great.
Or you can get yourself a canister filter, though some are expensive you can try looking at 501 canister filter or toms rapid canister filter. Either of these will run you around $22-35
Substrate:
You can go for plain gravel. Or spice it up and get flourite, eco complete, soilmaster select, aquasoil. Thats personal preference. I had plants grow great with just regular gravel, so getting fancy isnt always important
Lighing:
For a 10g I would get a incandescent light fixture and add 2-14w compact fluorescent bulbs giving you 2.8wpg (watts-per-gallon) which is enough to even make some plants red.. This fixture can be found at walmart or even petland discounts
Plants:
If you get the lighting such as the one i previously stated then nothing is stopping you. You can go from java moss to some dwarf hairgrass to other medium light plants.. You can use this website to get some plant information
www.plantgeek.net
Tank mates:
I would go for a school of tetras and maybe some cory cats, but thats totally up to you. You can also do shrimps with snails and some smaller fish..
Suggestions:
If you do get the lighting such as the one stated above I would also try looking into making a do-it-yourself CO2 (yeast/sugar/water mix) and maybe looking at some liquid/dry ferts.
Also if you do get plants, try and get as much as you can right away, so that way the tank cycles faster and you get less of a chance for an algae outbreak..