We've recently used Atelier de Moldura (atelierdemoldura.pt - although the point is, they have a physical location in Lisbon) as we needed a couple of things framed which had particular requirements. Most of the online places do not provide a service in relation to what goes in the frame, just the frame itself, if you see what I mean.
In our case, for a canvas to be stretched onto a stretcher frame, and then framed within a suitable antique-style wooden frame, came to 218€ for a roughly 60cm x 40cm canvas (visible area after framing) including materials, service and tax.
From what I can tell, the materials are more costly, the service less so, than the UK, and it levels out broadly similarly for what you end up with.
Many towns have a place which offers framing, but to be honest, the service and selection in the average medium to large town is poor. Art framers in the more formal sense are not widespread.