Hi Vaelia,
Welcome to NamePros. The new prices in domains may go up and down wildly for various reasons, such as promotions, sales venue, market conditions, and/or perception of the scarcity or abdundance of that particular domain.
The thing that I have come to understand is that it really doesn't matter where you are in the world, so long as you love to read and have access to the Internet and the time to do some research. After a period of time, you come to recognize trends in sales, pricing and demands for certain extensions.
There is information about domain sales regarding the .es extension within this forum, at dnjournal.com and you can search by extension only if you like at namebio.com.
Past sales of the Spainish extension .es range greatly from a $200.00 sale of arsa.es (05/07/07), Apartmentos.es for $40,370.00 on 06/27/07, DWS.es for $9,438.00 the week of June 2006 and recently, the sale of one.es for $115,710 on 07/04/07. None of these were any of my sales incidentally.
So, even though the general belief among many may be that .COM is the best investment as far as extension is concerned, my general belief is to diversify and include other country extesions if there is a market to support future sales.
Let me say also that country extensions give you an opportunity to come up with some pretty neat domain hacks, which are domains made up of words that include the country extension. Such as Doma.in, which is owned by a member of NamePros. Other examples include AboutJes.us and FixedMortgag.es, which are two I registered after reading here on NamePros, about domain hacks.
My advice to you Vaelia, would be to read widely on the subject of domaining, sign up for the dnjournal weekly newsletter which report sales of domain names across all extensions and when you feel puzzled, ask questions, because this should be fun and sometimes you can make some sales along the way, to ward off the naysayers.
Best wishes, Tommy.