It is my first trip to Italy, and I do not want to expend more that $250 USD per night on hotels, but I would like to fill safe and confortable. I am planning to visit Venice, Florence and Rome, so please give me your advice.

In Venice I loved www.lacalcina.com and have stayed there twice. It is in your price range.

You might want to try posting again with the country in your title: Italy Hotels

or

Italy Hotels up to 250, or even better, translate that to euro: about 175 euro.

You should try searching this forum using a key such as "Florence hotels", "inexpensive Florence Hotels" etc.

You can use venere.com to filter by price and this is also a starting point as they offer many traveler reviews.

Tripadvisor.com is a good cross reference for reviews.

"Comfortable" is defined differently by all of us. What makes you feel "safe"? A staffed front desk? Full service hotel? Location is a more touristy part of town? An owner occupied B&B?

Your post is really very generic. IMO.

t