I bought and used all of my recommended textbooks for the first year. I'm glad I did that. I didn't 'read' textbooks page by page, cover to cover- as I did in undergrad. There's just not sufficient time for that. I did, however, rely heavily on figures and their legends. If I wasn't getting the gist of a concept from the figure and legend, I'd read the accompanying text. This strategy worked well for me, and I'll continue to use it as I move forward. I'm keeping all of my first year texts, with the exception of Little Miller's (your dog dissection guide) and Smallwood (NCSU's second-semester large animal dissection guide- most schools use Dyce). I'll keep Big Miller's as a reference volume (yes, I bought it- yes, I used it), and pass Little Miller's off to the incoming class.
As for what you should do regarding textbooks, think about how you learn. The pace of vet school is very different than undergrad. Although I know a few students who read textbooks in the traditional sense, these are few and far between. I certainly didn't have time for that, nor did I need to, given the ppt support and extra guidance I received from studying figures/legends. I like having textbooks as a backup- a different presentation of material than what you'd hear from a prof.
I have a friend who didn't purchase one textbook (with the exception of anatomy) for first year. She did absolutely awesome, and didn't need texts at all.
If you're unsure of your learning style (and are not sure how much you'd prefer to rely on texts), it may be more prudent to rent. That way, you can try out your methods and wouldn't have lost much investment. I'm definitely in the 'pro-text' category, but this certainly isn't necessary for stellar performance in a school's curriculum.