Start with just one kind of lube. Don't feel you need to pick the "best" deep tissue lube. It's subjective, and you're better off trying a variety of lubes after you have learned how to work effectively with just one.
My school had us use oil in the early seforum.xxxes of our training, then cream as we got into more advanced levels of training. Since graduating, I have used at least a dozen different oils, several different creams, at least six different lotions, some massage gels, plain water, and plain hand lotion... all for "deep tissue" work. I have also done deeper work with absolutely no lubricant whatsoever. The key is to adapt your style of work to make the best use of whatever lube you are using at the moment.
If you use a lot of longer, faster strokes, you will probably need something with more glide. If you are doing fascial work, you may not want any lube, or perhaps you'll use just a bit of water or hand lotion. If you are doing NMT-type work, you can use just about anything, just not so much it gets slippery.
Since you are just getting started, it doesn't really matter what you use. Just pick something you like that is affordable. As your skills develop, you will be better able to evaluate the qualities of alternative lubricants.