In place of buying regular floatant, there are a couple of alternatives you could try.
1.) Ray Bergman, in his legendary & important book "Trout", suggests a floatant made from 2 ounces of paraffin dissolved in one pint of un-leaded gasoline. This sounds really good, but things have changed since Ray wrote that in the 1930's. My concern here is that a.) most candles are made from inferior wax these days & won't burn like the old ones did. You should make sure that you get a high quality of paraffin; & b.) gas is now 5, 7, 10, or 15% ethanol depending on where you buy it. Besides destroying combustible engines, will it work as well in this concoction as the older, straight gas did? Of course when using this floatant be careful lighting your pipe or any smokes, etc. Leaving it in the hot sun too long may also cause a problem, too. All this could lead to a problem much bigger than worrying about your dry fly floating high on the water!!!!
2.) Rainex, the windshield & auto glass treatment is supposed to work very well. You have to soak all your flies in it the night or day before to allow them to absorb the rainex. I've never done this but those that have report their flies floated well all day long without needing any more floatant or re-treating. Also, using a bottle of Rainex only as fly floatant rather than its intended use, the bottle should last most of your lifetime. Of course, there's the environmental concern, too. Evidently, there's a small chemical - like cloud of moisture that escapes from you fly the first time you put it in the water, but after that it doesn't seem to be an issue. Of course in Bergman's formula, you're putting a gas soaked fly in the water. It couldn't be much chemicals or gas leaving your flies & entering the water, but still, for those of you who are concerned it's something to think about.
Myself, I use a product called Mucilin. It's been around for ages & works well. A tin of it lasts a long time & it's also safe on fly lines, as you can treat a line with it too.
For those of you who are the make-it-yourself types, (or just really frugal) you might enjoy using your own floatant like the ones listed above.