This week Hobby Lobby has a sale on wood products, including balsa and basswood.
Finding GOOD balsa these days requires searching lots of stores. In 40 years of buying, I've learned hw to quickly identify the best wood, then I weigh those pieces that look likely to see if they meet my needs. Color tends to match density in balsa: the lighter the color, the lighter the wood. For glider wings I look for C-grain. For special applications like the balsa conical egglofters I used to build, I look for A-grain. For general use, it doesn't matter so much.
I'll also pass along a tip I learned from the MIT rocket club folks back in the 70s: buy all the good wood you can find. And these days it's a lot harder to find than it was in "the good old days". When you need it you won't be able to find what you need, so stock up. I have 3 SIG boxes 3x12x36" plus
2 of the 3x12x48" boxes that are all full of GOOD wood. REALLY GOOD wood...