I don't think you need to buy new buckets. As long as the buckets you have aren't too rough inside. I had an acetobacter infection in a cider batch and didn't feel it was necessary to replace everything. Granted I did ferment it in a glass carboy but had it been in a bucket I wouldn't have treated it much differently. If it was in a bucket the only thing I
would do differently is to fill the bucket with starsan solution and let it sit overnight or for a few hours and rub the starsan solution on the sides with a paper towel or something.
I think the only reason I got the infection to begin with was the Wyeast yeast I bought was from a LHBS that I had never gone to and I don't think the yeast was very viable. The fermentation never really took off which left it predisposed to infection. I was able to reisolate the yeast, however, and I have a new batch fermenting now from the reisolated yeast. No sign of infection this time.