Learn Danish: Butikken satte priserne op. - The shop raised the prices.

In Danish, when using a phrasal verb like sætte op (to raise / put up) in a main clause, the directional particle (op) usually comes after the direct object (priserne). Writing Butikken satte op priserne would sound unnatural to a native speaker.

Could I combine the verb and particle into a single word, like opsatte?

No, not for this meaning. The combined compound verb at opsætte does exist, but it means "to postpone" or "to set up/mount" (like a play or equipment). When you want to say "to raise" or "to increase," you must keep the words separate as sætte ... op.

What is the difference between using sætte op and a verb like stige when talking about prices?

Sætte op is transitive, meaning someone is actively doing the raising to an object (the shop is raising the prices). At stige (to rise/increase) is intransitive, meaning it happens without a direct object. If you just wanted to say "The prices rose" without mentioning the shop, you would say Priserne steg.

Is there another common verb I could use instead of sætte op in this context?

Yes, a very common and slightly more formal alternative is at hæve (to raise / to lift). You could say Butikken hævede priserne, which means exactly the same thing.