Hey beebee, cheaper SIM card setup is not possible as far as I know. As Tracy said, I do have a cell rental service and sell SIMs, my Movistar SIM goes for $95 with $60 in prepaid calling credit, very reasonably priced by any standard. You can get more info on [!-- BBCode auto-link start --][a href=\"http://www.onspanishtime.com/web/sim.htm\" target=\"_blank\"]http://www.onspanishtime.com/web/sim.htm[/a][!-- BBCode auto-link end --] although you have probably already seen it.
dimiterv, as long as it is a triband legally acquired phone it will work with the Movistar SIMs. Vodafone and Amena SIMs could give problems however as they are not as quality and hence cheaper and riskier.
Vodafone is decent but is the second rate carrier between Movistar (best) and Amena (worse). See coverage comparisons at [!-- BBCode auto-link start --][a href=\"http://www.onspanishtime.com/web/coverage_comparison.htm\" target=\"_blank\"]www.onspanishtime.com/web/coverage_comparison.htm[/a][!-- BBCode auto-link end --] . If you are going to be in main cities and towns you can get any of the SIMs but for smaller villages and mountain areas, go with Movistar for the best coverage.
Yes, the Vodafone deals mentioned bt dkmarsh are great but they will not last much after January 6th (The Epiphany here) [IMG SRC=\"modules/phpBB_14/images/smiles/icon_cry.gif\"] and it is a bit of a waste to buy another cell if you already have one.
Saludos,
jer...[addsig]