Accuracy of Chatradar service heavily depends on the method you choose. There are two locating methods available now: "trap link" method and "weather site" method.
There are multiple factors which come into play: Internet provider, quality of Internet in the area, specifics of mobile/home/office network used, pure luck, etc. Most of the time the result is accurate on the scale of cities. So, if the city name is provided, you can be quite confident that your chat buddy is physically in that city or really close to its borders.
This method is extremely accurate. The accuracy of weather site approach is few meters. You can try it yourself on the demo page. Keep in mind that few meters accuracy is achievable if and only if the person actually shared their location with the weather site when the site asked for it. Otherwise, it falls back to "trap link" method accuracy which is city accuracy.
Everything is free forever!
Not possible! Depends on the method you choose, the victim receives an innocent short link to some simple content chosen by you ("trap link" method), or just visit regular weather web-site ("weather site" method). Both are not suspicious in any way.
Weather web-site requires access to device location naturally, just because the weather depends on the location. Short links for "trap link" method are used quite often as well. You can easily say that you copied that link to funny image "from somewhere on the Internet". For example, in the description of this youtube video there are bit.ly links to online shops.
In other words, there is no way to catch you on something.
You can organize a genuine joke or surprise for your friends by "guessing" their current location out of nothing.
You can find out the location of your kids if they are lost, and come to meet them immediately.
In the case of trap link method, the person has to actually click your short link, otherwise it doesn't work.
If the victim uses VPN, the service will technically work, but will show wrong location.
It is your own responsibility to guarantee that no laws and/or privacy restrictions are violated by using this service. Please, make sure that you are given written consent from all the involved parties for all the actions you are willing to perform, strictly before using ChatRadar.