I have a styrofoam Leafcutter Bee Nesting Block to give away, if anybody in these forums keeps Mason Bees and Leafcutter Bees in their gardens. It is still in its original packaging; never been opened. I bought it when I was in the nursery last Winter, thinking I'd prepare for Spring, but only realized later there was not enough room in the bee house I already have. And I do not want to buy another bee house specifically for Leafcutter Bees (not in the next year or so, anyhow.) You'd need a little bee house to put it in.
Update: this nesting block is no longer available. I posted it on Craigslist and somebody picked it up right away.