Baby Monitor Flower

Hi, I live in a smallish city in OR and on our shortish street, I have no fence across the front. I am the flower lady in the area and sell flowers for .10 each on a card table and love to let the older people from the apartments walk by and see my flowers and it blesses them. But we have some bad vandals who for years have been coming into our front yards and stealing, breaking anything, just to be mean. Is there any kind of realistic security you have seen or used (not ideas that sound good), that can help or should I just put up a cyclone fence, they would probably just climb over it and I don't much money to spend on it. I would love to have like a laser light like when you go in the store and walk betweeen it it sounds off ??? Or baby monitors connect to a speaker in my room when the light flashes on at night and then alerts me to them being there and wakes me up ???? How much do you know. Please don't suggest security cameras unless you have used them and they have worked