I'm looking to get my first yixing. I don't know much about them. Of the ones on yunnan source, what would be a good first yixing. I guess it would be for raw puerh.
Depends on how much you want to spend. Here are a couple on the lower end. Keep in mind that the higher temperature it is fired at, the less porous it is going to be. The first one here is going to be less porous and the second more. The greater the porosity the more it will "take" from the tea. Personally I would not get a real porous one for your first pot.
There are many variables like clay type that can affect flavor. Price is going to drive this aspect to some degree. I wouldn't get to concerned about it at this juncture. Also understand that yixings do not improve all puerhs or oolongs. I have some that taste much better in a gaiwan. You will have to experiment...which is part of the fun.