I am saving up some bottles to reuse and noticed that Sam Adams bottles are one way bottles. Does this mean they can only be used one time or are they still ok to reuse for home brewing?
I've reused SA bottles many times without issue. They do tend to be thinner glass so you have to be careful moving them around so they don't bang together, but with the normal care reserved for delicate glass objects, they're fine.
The VAST majority of beer bottles are one-way bottles. Back in the 40's, all beer and soda was sold in refillable bottles, which were made of thicker glass. They were intended to be returned to the beer/soda bottler much the same way we return kegs to the brewery now. I can recall back in the 80's when i was pretty young returning soda bottles to the grocery store for reuse.
I read an article not long ago about a brewery that had a big stash of refillable bottles and sold beer in them (with a bottle deposit) to local customers. They are noticeably thicker than one-way bottles and typically have scratches on the outside from being reused over and over.