For cloning most LF tags you can use a blue cloner.
For cloning HF an ACR122U should work however, I do not know if the software is easy to use on mac.
The Proxmark3 is a really wonderful tool that can do both. It allows you to do a huge amount of stuff and really get into the nitty gritty bits of rfid. The proxmark just has a little bit of a learning curve to it.
You can probably get started pretty cheap by getting some ntag216 or ntag215 tags off of amazon. Those can be used with your phone and you can do a whole lot with them. As for the start stop on a car you may find The CaRFID thread to be of interest.