could you post a pic of the crack?

it sounds structural, and if it is a v1 r50, i dont know you can buy the v1 frames anymore.
i just crashed my v1 30 and i broke the frames, luckily i had a spare pair, but after the next crash it will likely be trashed or upgraded to a v2.

look for a raptor 50v2 crash kit. it will have blades, boom, head, flybar etc...
only thing is, being a v2 crash kit, the spindle will be for a v2, so you will not be able to use it.

id estimate, if you can get frames, around 60-80. (frames being about 30). if you cant get frames, id go with a v2 conversion kit. it will provide you with quite a few spare parts. you will still need the boom and flybar if you do that though.