Shop Aprons
Shop Aprons not only keep your staff, volunteers, and patrons clean, but they also keep people from accidentally putting tools in their pockets.
Styles
If someone spends a lot of time in the shop they might become particular about what kind of apron they use. There are some that have more pockets and some that evenly distribute their [and tool] weight using special back straps. For general use, get the simplest ones you can. Fancy straps only confuse new-comers, not to mention cost more.
Where to buy
Anywhere.
Pedros and Park Tools make bike specific aprons, but thinking outside the box most tool manufacturers make their own too -- regardless if they make car or wood-working tools. You can even contact restaurant supply places to see if they have chef / cook / waiter aprons with a couple pockets.