Inexpensive alarms for a shop?

I have a small shop that I would like to better protect from potential break-ins.

It's nothing fancy, it has a few power tools, the lawn tractor and stuff that I really don't want to have to replace again after my ex cleaned me out. I live in a remote area where people party at the creek and wander up our road.

I've installed a door jamb plate to help prevent kick-ins, I bolt the garage door from the inside, the windows are blocked with dowels, and are either covered with blinds or translucent film so no one can see in.

Do those brass covers that go behind the locksets really keep the door from breaking? I might get that too, although a steel door would be nice...but too expensive.

One of the my rottweilers is outside during the day, but both rotts stay inside at night. (The scary one is a spud-but she does the trick when she is called to do so, but ask her to stay outside--unthinkable !)

I am planning on replacing the deadbolt with a double keyed lock so someone coming in through a window will not be able to get the door open, but what I am asking about are those window alarms that sound when someone breaks the window---which is about the only way they are going to get in.

Any suggestions on what brand or anything else fairly cheap that will make this shop better protected? Bad times are ahead and I want to cover all my bases.