I would suggest something like a Trident clone that has adjustable airflow control (AFC). A clone will go for about $20.00. An experienced RDA user has a pretty good idea what kind of airflow they want, but if you're just getting onto RDA's then having the ability to try different airflow settings is a big plus.
I just started dripping this weekend and got a Trident clone. The airflow adjustability really helped me get the vape I want. A lot of people suggested the IGO-W to me and told me to just drill it out to get the airflow I want. Problem with that is I had no idea what airflow I wanted and if I drill it out in small steps I would eventually reach too big. I know how to drill a hole bigger, I just haven't figured out how to drill a hole smaller.
There are a few good low cost clones available with AFC, so I would look for one of those first. Other than that, just buy an inexpensive clone to test the waters and see if you like it. By the time you find out if you like it or not you will have gained the experience to setup and enjoy dripping and will already know what your next RDA will be.