How do you handle PCs requisitioning supplies from the Rebel Alliance? I don't mean when their Contribution rank goes up, but smaller, more day to day items, like stimpaks, grenades and such. In EotE, the PCs would just buy them out right, but PCs don't really have a revenue stream in AoR.

Apologies if this is covered in the book somewhere, but I looked and looked and couldn't find anything.

It really depends on the situation. As a default, I run the Alliance as cash strapped and much like EotE. Anything they capture, they have first dibs on (unless ordered otherwise). Most gear they have to purchase or steal unless it is mission specific and then they have to give it back at the end.

My GM has basically given an "anything that is reasonable" and that we don't have to give it back mission-to-mission unless it's very mission-specific (for example, we're going to Kashyyyk and I think they will want the jungle gear back after, but not the mods that the sharpshooter got from the Rebel tool shop and installed on her gun). The caveat is that the Rebellion doesn't always have what you want and may not give it to you if someone else has a greater proven need.

We also get paid mission-to-mission and this allows us to go out and afford stuff that the Rebels don't keep in stock, which is ours permanently since we, y'know, bought it with our salary.

I give the players their salary in credit - Base Bucks. This "money" can be used to buy items from the quartermaster on base.

It is a bit more abstract, but represents that the Alliance doesn't have a lot of money. Naturally, every base is going to have a weapons and equipment cache and players will want items.