vintage snap on bottom please help identify

[markitsnappy]

well i didn't buy the last box i came across because I wasn't sure it was real. This one is definitely real but i'd like some opinions as to the age and model and also if it's worth 200.00 price I'm going to pay. He was originally asking 350.00. I've looked on ebay and I don't see many bottoms of this vintage, mainly tops. I would love to restore it and find a matching top. thanks

 

[Lookin4'67Galaxieconv]

Looks like '50s vintage. Looks to be worth $200...though I'd try to get him down to $150-175.

Does it have castors or is that just the angle of the pic?