my WAG: standard A2 stock w/out buffer tube or extension - $20-25 since for some reason buttplates are hard to find. Detachable carry handle w/sights - $30-40. Carbine handguards - $7-10. Knight's cheese-grater plates - $10-15. Full length Knight's cheese-grater handguards - $20-30. The prices I'm throwing are what I've seen in the past, or paid for at one time within the past 2 years. Hope I'm not too far off.