In English, you might say ‘I want to exchange this for that’, in Spanish you would use por to say ‘for’ in this context.

English: I bought it for 12 euros.

Español: Lo compré por 12 euros.

English: She gave me 15 dollars in exchange for the lamp.

Español: Ella me dio 15 dólares por la lámpara.

English: I love your purse. Are you interested in exchanging it for my jacket?

Español: Me encanta tu bolso. ¿Te interesa cambiarlo por mi chaqueta?