Getting started with V-Mount batteries is not a cheap investment. Even the cheapest V-Mount Battery + Charger Kit can easily run you well over $300+ Dollars. If you're looking to power up camera gear with a V-Mount battery, here's a closer look at a more affordable option using this adapter that can accept two common Sony L Series (NP-F) type batteries.
The V-mount adapter runs two 7.4V batteries in series to output between 13V-16V, and also has a d-tap connector if you plan to run a cable to power up optional accessories. The v-mount battery plate can be found via ebay (seen here).
V-Mount Battery Adapter for Sony L Series NP-F Batteries
In order to use these adapters properly and to get the best results, you should be using two exact batteries. Although you can find many aftermarket Sony L Series batteries for cheap, they will often come in different sizes, capacities, and ratings. I suggest buying them in pairs and labeling them together. Check out some of the Sony L Series Batteries via Amazon (found here).
Sony L Series NP-F550, NP-F750, NP-F960, NP-F570, NP-F770, NP-F970