The stripper clip just barely slides into the top of the reciever, push the shells down and its loaded. clip doesn't go into the gun except for about a 1/4". It is removed before the bolt can close.
I would have no problem giving upwards to around 150 to 200 bucks on the shape of the gun. It is hard to find one in good to great shape, most of the ones I see are more or less gone and need a lot of help. I would say if it would be a reliable everyday shooter 150 is always good.
I bought some brass stripper clips from a guy off of ebay. I cant remember his ID but his come highly recommended. New made clips can be hit or miss and sometimes lightly oiling them can help. I have used Czech and never had problems with it. It is great stuff. Brass Fetcher has done testing on it. 148gr Czech FMJ (silver painted tip) I got mine from Aim Surplus. AIM Czech 7.62x54R 147grn FMJ Light Ball Czech 7.62x54R 147grn FMJ Light Ball
Make sure to pick up a cleaning kit. Not only is it a cool acessory but that "strange" shaped tool it used to check the firing pin protrustion which is very important. 7.62x54r.net is a excellent site that contains everything Mosin with very knowledgeable people on the boards. Just dont talk about sporterizing on there they dont take too kindly to that blasphemy.