bolts

Are all axis bolts interchangeable, meaning a bolt from a axis 30-06 will fit a axis action in 243

Yes, but you should always check head space after swapping the bolt.

and, of course, bolt heads may need to be changed out depending on cartridge. ( example, ,243 and 308 use same bolt head, but 223 or 204 is different).

Will a 30-06 bolt fit a 223 action, changing a 223 axis over to a 6.5 creedmoor and can buy a complete bolt out a 30-06 for $50.00

Yes, 30-06 and 6.5 Creedmoor share the same bolt head. The axis uses the same bolt length and action length regardless of caliber used. You may be able to pick up a new bolt head for less though.

Lone wolf just bought the 30-06 bolt for $50.00 and just sold my 223 bolt for $85.00 that's why I didn't just buy a new bolt head.

No problem, sounds like you made out then with some cash to spare!