Again, the most expensive part in the project. The casters.

What do i usually with old pallets?
Last time, believe it or not, i used it as a pallet.
The time before that, i used it to fir out walls when rebuilding a bath / shower.
½" thick wood just sitting there. and it just so happened that i needed to fir out the wall ½".

And, about your project. Worse comes to worse, you can feed it to your rocket stove.