You can get a basic spectrochemical analysis, viscosity test, fuel contamination and maybe TBN test for around $30 from several outfits. Wix, NAPA, Blackstone, Shell...
If you want testing to determine if an oil meets API or ILSAC standards, you'll need a fairly sophisticated lab. That will involve testing for several standards as laid down by the ASTM. That is quite expensive to do, and is how oil companies certify their products to carry approval ratings on the label.
