I took 1000mg of amoxicillin twice a day for about 6 months. I was terrified that it would destroy my gut flora and I would contract cdiff but in the end I didn't notice any adverse effects. Many people take yogurt with antibiotics but I didn't do that nor take probiotics.

Walking out of the pharmacy with 8 boxes of antibiotics at a time was a fun experience. I can't remember but in Australia I think it was less than $5 a box without insurance.