European Rail Travel - Italian train fares

Is it usually cheaper to buy train fares ahead of time online or at the station on the day of departure? I'm going to be making 4 train trips Aug-Sep:

Rome-Pisa 8/30
Pisa-Florence 8/30
Florence-Venice 9/1
Venice-Milan 9/3

Through raileurope.com I can get those for around $180. Any way to get them for cheaper? Would a Eurail pass be a better option? Thanks for your assistance.

Is it usually cheaper to buy train fares ahead of time online or at the station on the day of departure? I'm going to be making 4 train trips Aug-Sep:

Rome-Pisa 8/30
Pisa-Florence 8/30
Florence-Venice 9/1
Venice-Milan 9/3

Through raileurope.com I can get those for around $180. Any way to get them for cheaper? Would a Eurail pass be a better option? Thanks for your assistance.

Raileurope never offers the cheapest point-to-point fares, although they charge the standard prices for rail passes. The cheapest I've found is in advance on the Trenitalia website, but there have been problems with using U.S. credit cards to pay for the tickets. Try it - or use the site to calculate the fares and see whether an Italian rail-pass is cheaper.