My 10 gallon nano I had cost me about $25 at walmart. I got the tank, filter, hood and the light. I already had a heater for it. I just bought a better filter and a power head after I turned it into salt but the filter that came with it would have worked for a qt tank. I think they have 10 gallon set ups with heaters for like $10 more or something but I already had the heater so just got the one without the heater in it. You'll just need to add the sand and rock. I see them everywhere for like $10 for just the tank and nothing with it, just keep looking at wal-mart and different pet stores.
I use a QT and strongly suggest not adding sand or any substrate. You will need to be able to clean the bottom regularly (with a turkey baster) to keep your ammonia, nitrates, and nitrites from jumping.
I had an old 10 gal. I bought for $14 many years ago. Somewhere along the line, I bought a hang-on-back filter. I set this one up and it has been a life saver. I have since added a few things to it because they were either given to me free, I found them around the house, or bought them. A rotating powerhead set to low, a heater, a thermometer, a hydrometer that sticks to the glass (waste of money), prizm skimmer, and plastic egg crate over the top.
Your QT does not need much. I actually always use it now to hold new fish (one at a time) for a period of no less than 2 weeks. Longer if they show any signs of sickness or are not eating well.
I have LR in it to help with the biological filtration but if I were treating with meds I would not be using that. I did have a light but found that I had enough light in the room for my fish's needs and the light just raised the temp too high. The egg crate keeps any jumpers in and yet allows the water to remain cool.
I test my water in the 10 gal a MIN of once a week and usually more for these three things: ammonia, nitrite, and nitrate. I also keep pre-mixed saltwater ready for changes because smaller tanks' conditions can change rapidly. Because I test so much, I just purchased the test strips for use only on the QT. I haven't used them yet so I can't say whether they are good or not.
This may be more information than you wanted but perhaps some of it will be helpful. :away: