Don't try to buy it on internet from any random websites as it doesn't have any other major value other than making meth. Most of them are monitored by DEA by using Phishy webpages. My advice will be to purchase it from a manufacturer with shady past.
Be careful as I guess it's your first time in underground chemistry or chemistry at all.
Read some books on basic jr. College level chemistry and an organic lab manual. Then only try to do something