Honestly, I purchased 60 pounds of live sand for my first start up tank. I was cycled within 3 weeks, and I believe my sand has helped me tremendously in keeping my water stable and my tank healthy.
I wouldn't call it overrated, but maybe 60 pounds was too much. Adding a bag or two of live sand over the top of the cheaper sand would probably be wise and best. I think buying all your sand live is a waste of money. Two bags would be 40 pounds, and shouldn't be more than $70 dollars. Even one bag at $35 dollars wouldn't be a bad thing to add to your 75 gallon. Just pour it on top of your cheaper sand that you buy. It will help to get the other sand live faster, and helps with filtration.
Fish Sticks, the best thing you can do with your dead fish.