Craigslist/eBay maybe, unless you're thinking about keeping them to play with the newer games. Hold off a bit for the game to come out maybe to sell them.No more plastic instruments, I'm still trying to figure what to do with the old stuff.
This might just push me to buying a new console for this series again...Wow, current DLC library will work, as will legacy instruments!! All that and new songs, that's about all one could ask for, Christmas in March!
Buy Rock Band 4. They're going to make every effort to make the instruments forward-compatible.No more plastic instruments, I'm still trying to figure what to do with the old stuff.