I use Nicotine River and I've been happy with them. I haven't asked, but I imagine that they'd be willing to ship a small "test" sample, many vendors will do that. Shipping will probably not be free, but overall cost would be less.
If you are looking to get more into DIY or NEED any other supplies sometimes it's helpful to order from one vendor, after a certain price point my shipping is free with Nicotine River, although I can't remember what that price point is. But if you need syringes, extra bottles, etc., it might make sense to purchase it all from one place.
You may want to check around and see which wholesalers are closest to you, if you are looking to minimize costs. There are a few "big" trusted wholesale vendors at ECF, I know Nicotine Giant is one, Wizard labs is another (I believe they sell nicotine) but you could check the "approved vendors" forums, and there will likely be New Year's sales as well if you can wait.
Best of luck, Google will probably be your friend here.
Anna