Although not necessarily having a huge impact on the economy, a magical culture would likely make use of the following spells (I looked at 1st to 3rd level spells only) which would affect the way their society works:
- Comprehend Languages (1st). Professional translation services. For spoken communication, either someone on both sides of the conversation would need to cast this spell or the 3rd level Tongues spell. This would be great for diplomatic communications.
- Arcane Lock (2nd). Professional Locksmiths always employ someone with this spell for their more discerning clientele. A wizard could make a profession out of providing security services for those willing to pay. The spell lasts until dispelled. The magical locksmith might also employ the spell Glyph of Warding (3rd) to provide additional protection for sensitive items.
- Magic Mouth (2nd). A niche use I could see in a museum or zoo. Only a brief description though due to the 25 word limit. This spell lasts until dispelled so could be activated by adventurers who have stumbled on the crumbling ruins of a once great civilisation.
- Zone of Truth (2nd). This could be commonly employed during court cases or interrogations. I also see it being used during business transactions. Speak with Dead (3rd) would also be employed in certain cases. Even though the responses might be cryptic, it would still help narrow down the suspects.
- Streets would likely be lit up by continual flame (2nd), you can even employ these spells underwater to light up canals. Lamplighters would be employed to keep the spells running for when troublesome apprentices snuff out the flames (can a darkness spell snuff out a continual flame effect? If not then I guess troublesome journeymen are running around dispelling them). Incidentally, continual flame spells will likely cause a town or city lit by them to have a more extensive night light instead of everyone turning in when the sun goes down.