My friend and I are trying to get from Florence to Nice in May.
What's the best most cost-effective way to get there?

I cannot see any cheap flights from Florence or Pisa to Nice, so I guess the only reasonable way would be by train.
Thanks.
NIck is right...the train is easiest...you will need to change to a French train at the border. From there a relatively short trip to NIce. Have you sorted out your Cote d'Azur accomodations?
We've done the trip by train a number of times.
It is not easy. I think the minimum number of train changes is two, and the minimum time is over six hours.
The cheapest way with advance purchase is by train via Milan booked around 120 days in advance, if you can get hold of the very cheapest €9 advance fares for both Florence-Milan and Milan-Ventimiglia. This will give an overall fare of €25.10.
The cheapest sensible way by train purchased on the day of travel uses Regional trains for Florence-Pisa and Genoa-Ventimiglia-Nice, and an InterCity train from Pisa to Genoa and costs €45.70 overall. Connections using InterCity trains from Genoa to Ventimiglia cost only €5 more and can be faster.
The route via Pisa can be bought for a total of €32.90 if you are able to purchase €9 advance fares for Pisa-Genoa and Genoa-Ventimiglia. There are no advance reductions for Florence-Pisa and Ventimiglia-Nice.
There is also a direct Eurolines bus. Depending on day of week, this arrives in Nice at midnight or 4 am, and the bus stop is in a remote location near to the airport. This is a major drawback.
Edited: 1:56 pm, December 29, 2012We are thinking of staying in Villefranche-sur-mer. Do you have any recommendations?
Thanks for all the good tips.
Not sure what your budget is...but I would suggest the Hotel Darse in Villefranche.
www.hoteldeladarse.com/alpes-maritimes/
tripadvisor.com/Hotel_Review-g187246-d259712…
The Hotel Welcome is great as well if it fits your budget...
Thanks. Actually I had reserve that hotel but found out there is no elevator. Do you know Hotel le Provecal? The location is important.
Not sure what you marn by "location is important". Some parts of Villefranche are very steep and the Provencal is certainly "up the hill". If you have any mobility issues, the walk down to the harbour will be fine....back up, not so much.
The Hotel Welcome is right on the water...