The publishers update the textbooks regularly simply to keep people buying new ones, so often there is very little difference (and let's face it, first year uni maths isn't going to change that much from year to year, is it). You might have some problems with the page number references for extra exercises not matching up if you try to use the old edition, that's about all.do you know if therez much difference between the 9th and the 10th edition of that textbook? and how much are you planning on selling that book for??
With some subjects you can just borrow an older edition of the textbook from the library (one that's not on short term loan, obviously) and just keep renewing it every 3-4 weeks. It is surprising how many people will put a thousand reservations on the latest edition and not think to look at the older one.