There's so much stuff out there it's hard to give a recommendation. I am partial to the Aspire zelos 50 watt mod with an N2 topper starter kit, but the picos get great reviews from new vapers and the Melo III tank is pretty versatile. If you want something a bit more powerful, you'd be looking at sub0hm startups which I don't know that much about. If you want the option of both I might choose an inexpensive sub0hm setup and buy a MTL tank separately (you should be able to use it on your other mod) that way you'll have a few options to try. If you are pretty sure you'd like a MTL setup, there are some good, inexpensive options.
As far as juice, I'd recommend taste testing if you can at a B&M to get a sense of what you like, and if you can't do that, maybe a juice sampler set with some different options in small quantities so you can try various things without committing to a big purchase, at first.
Best of luck,
Anna