While you don't state budget, there are some other questions to ask.
what do you do in the Garage? Workshop? hang out area for the guys? what music profile do you prefer? what type of listening?
what will you use to be driving zone 3? onboard amps/speaker terminals or pre-outs to an outboard amp?
Generally speaking, and as previously mentioned, you don't need to spend a lot. - find some used speakers and be done - craigslist, goodwill, thrift store,etc.
also considering placement and what you do in the space as well, i.e. do you make a lot of dust? can impact your decision process.
typical indoor/outdoor - type speakers with an integrated bracket could do you very well and many can be found for less than 100/pr
. ( parts-express.com or outdoorspeakerdepot.com) just make sure you get ones with at least a 5" woofer.
if you need durable, but potentially powerful, and mountable - check out the stage right PA speakers at monoprice -both passive and powered versions
good luck, rock on