Oh, and of course I'll tell my landlord what I intend to do before I do it. Hopefully, they'll give me the bars. But if they don't, they seem to be pretty cool about working with me on how I plan to use the space.

One of our rental houses has basement windows that made the single female tenant uneasy. I looked at those burglar bars (and found locally Lowe's was least expensive) but I didn't put them in because of local fire code. (As an aside we do provide curtains or miniblinds for basement windows as well for extra privacy.)

Anyway, one time a local police detective told me motion lights are an excellent deterrent. The surprise of the light startles anyone lurking around, and he told me police on patrol at night learn which houses typically have lights on all night, which ones don't, and so if they see lights on where they are usually off they'll take a closer look in case someone has triggered a motion light.

He also told me too much landscaping provides hiding places, but thorny bushes strategically placed at windows are great deterrents. It's hard to be a sneaky thief when one's clothing gets all tangled up and skin gets cut by thorns. ;)

We already have motion lights in place so what I did do is utilize landscaping. I planted the thorniest bushes I could find right in front of the windows. Rose bushes or barberry. (Be sure to get those pot grown and a good mature size. Lowe's and Home Depot sometimes have good choices, but nurseries often typically offer larger, more mature plants sizes.) Some varieties of roses have 'soft' thorns, but others have wicked bad thorns, large sharp ones with small prickly ones in between. Even heavy winter clothes are not protection, they would leave one in a tangled up mess. I also put in some really thorny barberry bushes (inexpensive, no fuss, they grow fast, too).

It's economical, can be pretty too, but you do need to watch little ones closely. I've offered some links below.

Here's a quote from this link: Anyone who has crossed a thorny plant or rubbed it the wrong way (pun intended) knows that they can inflict immediate and tremendous pain upon the interloper. Some thorns are sharp and needle-like, others are razor-like, and some would challenge the most devious of torture devices that a Department of Homeland Security engineer might possibly devise!...Nothing says "Keep Out!" like a row of tall barberries or Scottish roses!

Home security and perimeter protection

Thorny bushes and shrubs planted against your house around windows will help deter people from trying to crawl through. Anything that makes it harder to enter your home or decreases hiding areas will help increase your home security. That quote is from Guardian Alarms

Here are Google Image results of Japanese barberry, some of the photos show the sharp thorns hidden by the leaves in warm weather. Hurts to even prune them!

Lots of info out there, google "thorny bushes burglar deterrent" or "thorny bushes home security".

I am trying to find some inside window security gates . I'Ve been to Lowe's. Something I can install myself.

There's no such thing.
The ones from Lowes can be cut with a simple bolt cutter.
Anything else is custom-fabricated and excruciatingly expensive.

There's a legion of grinning "security people" who will be MORE THAN HAPPY to tell you that, well, um, yeah, it's actually going to cost $400 a window to do it right.

And then, you know, they need to secure the doors as well, another $3000

the "affordable" guy turns out to cost $7000 or so.