Buying a blade grinder is a waste of money, but burr grinders range from $50 to $500 and while there is a significant quality difference, it can be reasonable to buy one at the cheaper end.
You can do OK with a blade grinder. I used to have one from Target, and I would grind in two or three stages, stirring the grounds with my finger (!) in between to get more consistent grinds.
A blade grinder is fundamentally incapable of producing remotely uniform particle sizes unless you're willing to sift the result and discard a substantial portion of the coffee. Stale pre-ground coffee will usually give better results and is typically the same price as beans.