I highly recommend you save money another way. If your yeast is bad, you may not know it until after you've put a lot of money and time into brewing and fermenting your beer, only to realize it has off flavors in the end. That's not a happy feeling.
Fortunately, yeast is one place you can save money. I recommend starting with a good commercial strain. You can build your starters a little big on purpose, and save the leftovers to make a starter for your next batch. If you're brewing a modest gravity beer, you can harvest yeast from the fermenter after fermentation is complete and just use that if you are brewing again soon. Paying $8/batch for liquid yeast adds up, but with these techniques, you don't have to be out all that money, nor do you have to risk a wild strain that may not make good beer.