Budget accomodation in Marrakech: prior booking?

I will probably go in Marrakech for my first time at the beginning of next September. Having only a couple of days off work I will probably stay there for 3/4 days. Anyway I was wondering if, considering tha fact I will get at Marrakech airport around 1100pm, it would be better to book an hostel or a riad beforehand. And, in any case, do you have any tip for me? I'd like to stay in the medina.
Thanks

mc

Arriving that late at night, yes, book in advance. Try the Hotel Sherazade, N. 3 Derb Djamaa
reservation@hotelsherazade.com
It is in the medina, clean and reasonable, but kind of hard to find.
Or, less desirable, the Grand Hotel Tazi.
That time of night your taxi fare will be about 50% more than the daytime rate. What is the daytime rate? Depends on your negotiating skills, but about 50 dirhams.

Do you know any cheap riads I could sleep in and book from the internet?

Check out this page

Marrakesh Accommodation - Riads, etc.