Data in Portugal?

[sleepy]

I am going to be in Portugal on Monday for about a week.
I have been searching here, but I could not find any precise information on prepaid options for data access in Portugal.

I have browsed through the operators sites and I may have found something from Vodafone (to be better investigated on site).
It is quite strange that Vodafone seems to be the best option, since I never found that Vodafone-related national operators have good data plans (starting from Italy... It is a pity, since I am using Vodafone post-paid in Italy for voice calls and I started to use mobile data with Vodafone, but then I had to leave them since all other operators have far better deals).
It would be the first (welcome) time since a long time!

Anyway, I have of course already all that is needed. Therefore I am not very much interested to get options where they want to sell you the USB-key bundled or similar with the data option (how many USB keys should we have in the mind of the operators? ).

High speed is of course preferable, but any type of affordable connection (even plain vanilla GPRS) would be fine!

I thank you for any help in advance!

Sleepy