The best way to save money is to shop online. Pet stores have a lot of overhead, think about it, they have to pay employees, have to furnish the store with displays, have to pay utilities on all their facilities and take care of animals.. they have to do this and still make a profit, so they jack up the price on each item. There's also the unfortunate side effect that when you shop there you're supporting an evil enterprise that profits from the misery of the animals housed at their facilities.
I do all my shopping here: http://www.fosterandsmithaquatics.com
all of the items are marked down $10-20 lower than pet stores and everything ships very a very reasonable flat rate of $9 no matter how heavy or how much you order. I suggest the 25watt hydor theo heater or similar--it is adjustable and much higher quality than a pre-set or a heater pad. You will also want to get a liquid master test kit and perhaps some additional decor items--it's best to put as much as you can of the things you need on one order. F&S also sells some very reasonable small tanks, such as the Marineland Eclipse line. They are well designed and of decent quality.