I have a 50th anniversary MkII blued with the standard barrel. It has a B-Square clamp-on mount that wears a $35 BSA red dot. I installed the B-Square with red Locktite. It creeps a little in several hundreds of shots. It attracts attention at the range and shoots like the proverbial laser beam.
I bought everything new and have less than $400 in it.
Build a man a fire and he'll be warm the rest of the day. Set a man on fire, he'll be warm the rest of his life.