A simple plat of survey will cost you between $250-$400. The old survey, if you can find one, will only show the encroachments at the time the survey. That means if a fence, new sidewalk, porch, addition, garage, etc. was built since the old survey was done, you may not know if you have an issue. Also, most lenders will not accept a survey that is greater than 6 months old.
The survey should cost between $200 and $250. If you are quoted more than that for a single family lot, then you are paying too much.
The only way to get an earlier survey is to talk to a prior purchaser of that property as surveys are not part of a public record.
This answer does not constitute legal advice and does not and is not intended to create an attorney-client relationship. The law may vary depending on the state in which you reside. It is intended only to give some direction in which to seek assistance.