You will need at least a few thousand to your name to pay for the skip tracing, a few postcards, signs, software, gas etc.

If wholesaling a good place to start would just be driving around your local community looking for properties and taking those addresses down and skip tracing the owner somehow if you are on limited funds, however if you have money available you could leverage that into a site such as prop stream where you could put together a list of properties with a certain criteria and then batch skip that list of homes with something like REI skip and look for properties all over the united states. it really just depend on where you are financially and how much time you have but there are tons of youtube videos you could check out that would show you how to get started no matter which path you choose.

If you are looking for many properties, spending on sites has a better chance of being worth it, but if you are looking for just one, like a next property, personal letters after building a list on List Source is a good first step or using an app like Deal Machine to skip trace and mail properties that you already judged to be of value to you.

If you like wallpaper go to town on your own house but skip the rental, it is likely to get scratched and need frequent replacement increasing your time and costs. 

So, I am going to skip answering, but I will tell you reason people like Warren Buffet makes millions of dollars in the stock market.

What are the best ways to skip trace especially on a low budget?

I suppose if I could get seller financing I could potentially skip that hurdle altogether though.

My questions which site is the best skip trace for a beginner? 

I pull lists off of an auditor site and skip trace them to find names of people to call.

If you see laddering (bricks breaking along the mortar lines), bricks leaning, tuck pointing missing, bad porches, etc then you can skip the property.