I can imagine how frustrating that must have been getting shaken down like that. It may have had somethign to do with having a hand out for a bribe, but I'll bet it was more related to the aduaneros political leanings...
I just got three books in my monthly mail shipment from the States. Brand new, English-language books ordered from Amazon. The commercial invoice/declaration sent by DHL clearly labeled the contents as books and papers, and coming from the US, I'm sure the aduaneros realized the contents were in English.
BTW - getting books from the States is not necessarily outrageously expensive, at least not if you don't order too many and too often (someone made the comment about having books sent from the States that seemed as though they were saying it was expensive).
I ordered three books from Amazon - two hard backs (one of 900 pages, the other about 600) and a large paperback (longer and wider than "normal"). Total cost from Amazon was $45.
I use USABox.com to forward my mail to me. I pay $32 a month for the service, and am allowed up to 4 pounds sent once a month for that price. They also will re-pack all your mail so that if you get a couple of different boxes, for exmaple, the will unpack it and repack to reduce size and number of boxes. I've seen other mail forwarding places mentioned previously as well, that I'm sure are as good at least, if not better.
With all my other mail (including a couple of magazines as well) and the books together, the weight of the package was 5.5 pounds. It cost me an extra $5.50 to send the books.
I got my shipment in three days. No worries about things disappearing - came straight to my door this morning.
I don't know what it costs to ship direct from Amazon. Nor have I had things sent through regular international mail, so I can't comment on that. But if you have a mail forwarding service anyway - you almost can't lose.
I've bought hardback books here of around 500-600 pages, English language (at Cuspide mostly) and have paid a good $120 pesos. That was when the exchange rate closer to 3 to 1 than the near 4 to 1 we are seeing today, so it was almost $40 US to buy a book like that. Even at the current exchange rate with the same price as a year or so ago, that would be a little over $30 US. I don't know what the costs are now because I stopped buying them here locally.
My three books averaged nearly $17 US with shipping included. Can't beat that!
Even factoring in the shipping costs for my forwarding service (which isn't quite right because I really use that to get my mail anyway), it would still be an average of only $27 US a book, still cheaper than buying locally.
Of course, this doesn't count used books. I haven't tried one of the local used book locations mentioned in the forum, but one day...