Looking for recommendations for a good beginner pen [@trinnyroseink] [Altered Society] [Post Falls, Idaho] [US]

Hey all! I have reached the part of my apprenticeship where I have started tattooing on grapefruits and fake skin. I am primarily learning on coils and use both my mentors old coils as well as a couple that were gifted to me by one of the other shop artists. However I also have been allowed to practice using my mentor's pen a couple of times to feel the difference in how the machines work.

All of the artists in the shop primarily use pens, and while I am enjoying the coil, I feel like it would be beneficial to be able to have both at my disposal. My mentor has even encouraged me to start looking into a pen of my own in the future. This isn't an immediate purchase I'm planning to make, maybe in the next few months, but I want to know what a decent machine would be for a beginner. I'm not in a position where I'd be comfortable dropping 1k+ on a pen, but obviously I don't want to buy Amazon garbage either. I'm hoping to stay around 500-600 or less for my first one.

If anyone has recommendations for a good beginners machine please let me know! Thanks in advance!