I think you mean "thinking about". The difference is if you you considering or deciding whether to buy something, you are "thinking about" buying; but if you already have bought something, you might be "thinking of" that thing (remembering it).
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
habibaelgindy of or about?Strangely, I almost always use "of". I was thinking of buying something.