Normally its better to buy the parts sperate since kits don't come ith the best equipment. However if you do have to buy a kit I suggest the Marineland Biowheel Kit. Here's a link:
HI Jay and welcome to the forum!
Are you deciding between a 10 gallon and a 20 gallon only or can you go bigger?
Of the two options I would recommend a 20 gallon long as you'll have more stocking options than with a 10 gallon high.
The Pleco really shouldn't be in either tank though in a pinch a 20 long will do.
A small pleco like a clown pleco would do okay in a 20 gal long, but the ever-popular BN plecos are a bit too big (and don't get a common pleco!). Cories aren't suitable for a 10 gal, so if you want those, go for the 20
Fish Keeper Jay
As a newbie myself, I would recommend at the very least a 30 gallon tank. If you have the space and greenbacks, then I would go for a 40 gal. There are several reasons I say this. First, you most likely won't be able to get the number of fish that you want in a 10 or 20 gal. Second, if you like bigger fish that's even more limiting. Third, and this one to me is most important, the water will be more stable in a larger tank.
It's VERY EASY to overstock a smaller tank. This is not to say that you can not overstock large tanks, but small tanks won't allow large numbers of even small fish. If you are not good with stocking a tank and it's more of a numbers game for you, you will likely overstock a 10 or 20 gal tank. TexasDomer is one of the best for stocking advice. Anders247 is another
Provided you have all of the same factors with a 10 or 20 gal as you would a 40 gal, the 40 gal should be easier to care for.
If you haven't purchased anything yet, I would also recommend doing some reading on this forum first. Click on any words that are blue, such as nitrogen cycle, to read about them. If you don't already know, become VERY familiar with the nitrogen cycle.
Understand that a stable pH is more important than achieving a specific pH. In other words a steady 8.2 is better than fluctuating 2 tenths on either side of 7. Unless you have problematic water, you won't need to buffer the pH to any specific level.
Don't be afraid to ask. There are some pretty awesome people on this site
If 20 is one of your options, definitely choose that over a 10. And if you're willing and able to go up higher, do that, too. Just make sure you have the space and support for it because even at a 20 gallon tank level, it gets really heavy with all the water and contents.
We are so close to Black Friday, so take a look at Petco and Petsmart's BF deals and see if you can take advantage of that. I'm looking forward to the 50% off plants at Petco.
Definitely a 20 over a 10. And if you can, definitely a 20 long over a 20 high.
Agree, 20 is good! I started off with a 10 gallon then went to a 20 gallon and then went to a 40 breeder. I really suggest if you have money and space go for a 40. In the end it actually saves you money since if you buy equipment for a 20 now and then a couple months later you want to upgrade, most of the equipment you bought for the 20 is useless. However most kits for 20 gallons are 20 highs, 20 long are better though since for most fish length is more important than height. If you actually have time and aren't in a rush and rethinking about getting a kit and build from scratch I suggest you wait for the next $1 per gallon sale at petco! if you can get a 20 long than you can get a 29 gallon. I also feel like a 10 gallon shouldn't be a starter kit especially if your looking for a community tank. Despite the pictures there really aren't a lot of fish from the common pet store that you can have in a 10 gallon.