When in Rome save money as the Romans do

BREAKFAST

EAT YOUR BREAKFAST STANDING UP...If you want to have breakfast at a bar, have your cornetto and cappuccino at the counter because Roman bars usually charge more if you sit at a table.

GET YOUR CORNETTO  (Croissant) FROM A CORNETTERIA...if you buy cornetti directly from the baker you wil pay less than at the bar.  In the Prati area you can find a cornetteria on Via G.G. Belli 63.  Freshly baked cornetti are available from midnight onwards.

LUNCH

Go to a PANINOTECA...lots of choice of panini and tramezzini (tramezzini are sandwiches).

Have pizza by the grams at the PIZZA AL TAGLIO shops. Many choices of pizza and you can buy as much or as little as you like.

Go to MONDO ARANCINA, a Sicilian fast food chain in Rome. Here you can get arancine with different fillings, pizza, sfincione, genovesi and other Sicilian delights. In the Prati area Mondo Arancina is in Via Marcantonio Colonna 38.  There is one on Via Tuscolana, in Piazzale Clodio, Via Oderisi da Gubbio and in Via della Vite.

Get a made-to-order panino from a supermarket or grocery shop. It's cheaper. 

Take a bus instead of a taxi, it's much cheaper, and you will also avoid being swindled by the notorious Roman taxi drivers.