Weliketoparty,
The older Dynamos were nice tables, better built than Tournament Soccer, and from the pictures you posted that one looks to be in good shape. Price is subjective to some degree because if you really like it and enjoy playing on it, then it's really up to you if it's worth it. I'd offer $300 and see if you can get it for $350-$400. My biggest concern would be the fact that those look like the old style Dynamo men which are pretty hard to come by. If the table comes with some replacement men, along with other parts like bearings, springs, etc. that would protect your investment for a period down the road.
Good luck!
Tyler