- Should I buy/purchase web hosting?
- Should I buy/purchase Adobe Photoshop?
- Should I buy/purchase this car?
- Should I buy/purchase this land?
When should I use buy and purchase? Why?
- Should I buy/purchase web hosting?
- Should I buy/purchase Adobe Photoshop?
- Should I buy/purchase this car?
- Should I buy/purchase this land?
When should I use buy and purchase? Why?
In meaning, they're exactly the same. You can interchange fairly freely. Looking at the definitions on The Free Dictionary, each is used to define the other.
In practice, "purchase" is of a higher register than "buy", making it more formal. You might find "purchase" in a legal document, or regarding government expenditure, whereas "buy" is perhaps more for daily use.
The only other discernible difference I can think of is that "purchase" has the noun "purchase/s" whereas "buy" doesn't.
In your examples, simply consider the formality required for the context.