Need some help with oils, please.

Any mineral spirit thinner will work.

As for the manufacturer, just go to an art supply store, and anything you find will be fine, so just look for whatever the cheaper option you can get is.

Colours, you wish to get at least all of the primary colours, plus white, black, raw umber, burnt umber, sepia, orchre, yellow ochre, etc.

If you have a Hobby Lobby in your area, go to their web page and check when the 40% coupon is available, usually once a month for like a week or so. I picked up a Reeve's 24 tube set for $6 or $7  a while back. I can mix custom colors and it really gives you a greater color range for detailing with washes and filtering. I use regular paint thinner from Walmart. It works great!

For weathering, any brand of oil will do, but for figure painting I highly recommend Winsor & Newton.  These are a little more expensive, but have the finest pigments available.  For thinning, Mineral Spirits or oderless Turpenoid is what I use.  You can find these products at most Craft Stores.  I get mine at the local Michaels.

Regards,  Rick

Roger that on the Turpenoid.

Turpenoid is a more highly refined turpentine and works well with oil paints.  Most mineral spirits and/or turpentine (white spirits/turps) from the hardware store seems to be a little 'hotter' than Turpenoid and may affect the underlying paints in variable unpredictable manners.