Alaşehir is in Aegean Turkey.
As Philadelphia, the city was founded in 189 BC by the king of Pergamon. Most of the city is quite new, as the town was burned by the Greek and Turkish forces during the Turkish War of Independence. Today Alaşehir is an agricultural center and market town, rather run-down, with little to see and not much to recommend it. (If you're interested in a traditional market town for Turkish farming country, Akhisar is much nicer.)
There's a monument in Alaşehir celebrating the liberation of the town in the Turkish War of Independence, which the locals are quite proud of, despite its resemblance to pretty much every other liberation monument in every other Turkish town that played a role in the war. There's also the ruins of the Church of St. John (St. Jean Kilesesi), though it's only open rarely (possibly by appointment), and locals seem uncertain of exactly when the church can be visited. There's also a bit of a ruined wall by the bus station, and a fake castle down the road.
Aside from walking around the town, it's possible to check out the market, and buy fresh produce.
Fresh produce, on market days (of which Saturday is one, though there may be others).
If you're in Alaşehir, it's probably because you want to see the Seven Churches of Asia. Two of these churches are nearby, Sardis in Salihli, and Laodicea, near Denizli. Sardis can be reached by train or bus, while Denizli can only be directly reached by bus or (or possibly minibus) or private transportation.