Obtaining a cell phone in Italy

There are a few different options you could consider......

1. Buy an inexpensive PAYG phone in Italy when you arrive there. It will also work in Spain although you'll be "roaming" so the costs will be slightly higher. It's important to ensure that you'll be able to top-up the minutes after you leave the country-of-purchase.
2. Buy an inexpensive phone from one of the travel phone firms such as Roam Simple, Cellular Abroad, Telestial, Mobal or EuroBuzz (they run about $40). These often come with a U.K. number, but have consistent rates throughout Europe and often use post-paid billing (calls charged to a credit card). For basic phone service, these can be quite cost effective (but if you add data, the costs increase).
3. Buy an unlocked quad-band GSM phone off E-Bay or Amazon, and use it either with a SIM card purchased in Europe or a SIM card from one of the travel phone firms. One advantage of this approach is that you'll have a wider variety of phones to choose from, and will be able to buy something that fits your criteria. Also, you'll be able to use it on future travels.

I think the fact you use cricket in the U.S. means you have an unlocked phone. If so get the Vodafone holiday SIM in Italy. While you have an Italian phone number I am pretty sure it will work in Spain.

Vodafone Holiday plan or TIM Welcome plan are the best options with a smart phone, because they includes a lot of data (2Gb). But if are using a simple dumb phone to make only phone calls, there are cheaper plans. For example if you don't need internet at all, there is TIM 9 which charges 7 euro to activate, then charges 9 cents a minute for outgoing calls and 9 cents per SMS message (outgoing). Incoming calls/SMS are free).
If you are over 60, there is also TIM 60+, which includes internet (1gb) and costs only 12 euro.
Vodafone has similar cheaper plans, such as the flexi start, with only 100mb, with 400 min+100sms all for 10 euro (4 weeks).

The advantage of the Holiday plan (Vodafone) or the Welcome plan (TIM), which are geared for foreign tourists, is that those plans include a few hundreds minutes of international calls and a few hundred international SMS text messages which you can use to call/text the US/Canada for example. Whereas the cheaper plans I mentioned earlier would cost you much more to call/text outside of Italy. Also the above tourist plans have a lot of data (2Gb) which is a lot for a few weeks stay.