Seville can be expensive, tricky to accommodate in and impossible to park. Lucia's hosting is 20 minutes walk to historic center and 5 minutes walk to trendy, cool boroughs of Seville's north. On street parking is indeed free and possible after few minutes of searching, which is fantastic.
In the flat itself you'll live with Lucia and her son, so measure expectations to be a guest they let stay rather than hotel-like demanding customer. For a calmed down, no partying stay this is great host.