I would suggest Walmart's Hawkeye 5 gallon tank..comes w/filter/food (I didn't use) and water conditioner. I purchased mines Monday for $27.
*Con-the filter is too strong, so will require fine tuning ( haven't learn to fix it myself).
*Pro- Walmart will accept a return on the tank even after you have opened and used the product if for any reason you are not satisfied. I am not sure on the time frame to return the item.
And for the heater.. Petsmart has a sale starting Friday, so check them out in-stores. Just make sure you get a quality heater so you are not wasting your money trying to replace or upgrade. I am still determining if the one I have now is good. Also, please buy a floating thermostat. I purchased the one you stick on the tank ($2-Petsmart) and I do not think it is giving me an accurate reading. Now, I have to go out and buy a floating thermostat ($4-5 Petsmart, may can find cheaper at Walmart/Amazon). But, I can honestly say I wasted over $30 dollars on items I ended up replacing b/c of the quality

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Good Luck...just shop around & read buyer reviews!!!