Decent but cheap camera system:
https://www.newegg.com/Product/Product.aspx?Item=9SIA46G57R2213
Buy the optional bigger hard drive. The cameras are bigger than you might think, this is actually a bonus... You don't want to covertly capture the thieve's image, you want them to see the cameras and decide to move on to easier targets. The dome cameras are about 6-7 inches in diameter, and the other cameras are about 10-12 long from the mounting surface. The autodetect/record does not work on the first two channels, not sure why, but it is a known "feature", you can trigger them from a different camera or from IR sensor, door switch, etc. The cameras are all powered over IP, comes with eight 100 foot cables but you'll probably want to buy cable and connectors for a better looking install (Lowes has decent indoor/outdoor bulk cable) and Cables and Kits in Florida has decent prices on connectors, crimpers, and direct burial ethernet cable.
And all that said, I real "professional" alarm system may get your insurance rates lower.
As well as installing a security camera system, you might also consider installing a few dummy security cameras too as they're even cheaper. (perhaps in places you might not have mounted a security camera anyway, for instance in places that wiring would have been too tricky to do easily) As simply their existence there will help be a little extra deterrent.