Turn a small drill press into a Bore/ Hone. Bolt it to the top of your engine block & do your own machining .

Yunick13 said
$70 for reject pistons
$239 for a portable bandsaw to hack the top of the pistons rendering them useless
$300 + to see if home boring a block is possible.
$4 gal. Kerosene

+ the mag drill and whatever "attachments" "boring tools" "honing tools"