Karina, generally speaking, you don't really need bilingual books--you just need books in the minority language, in Spanish. Maybe your local library would even have a section of children's books in Spanish, or would be willing to start growing one? Although I've built up a large home library of books in our minority language, over the years, it's also true that I've taken full advantage of the collection of minority language books available at the library in town.
As for obtaining Spanish books online in thrifty ways, I invite others out there to offer suggestions!
Adam Beck is the founder of Bilingual Monkeys and The Bilingual Zoo, and the author of the popular book Maximize Your Child's Bilingual Ability amzn.to/22XKuCt and the humorous novel How I Lost My Ear amzn.to/2EsjVRS, both available worldwide. Please support The Bilingual Zoo through Adam's Patreon page www.patreon.com/bilingualmonkeys.
I have had some luck using "Craig's List" type sites in Spanish speaking countries. Just like in the U.S., you find people looking to unload their children's libraries after their kids have moved out. Usually the exchange rate works in your favor. The problem, of course, is shipping. If you have relatives or friends in a certain country, this can be negated somewhat by having them pick up the books and packing them in their luggage next time they are in the states.
The cheapest way is to borrow books from public libraries. You can keep them for several weeks.
Another way, if you have family overseas, ask them to buy some books for you, and bring them when visiting.
Also, the public libraries, at least here in Arizona do many book sales where you can get books as cheap as $1. Also, find out which libraries in your city offer bilingual (English-Spanish) story times. In some special celebrations they give away books for free.
Check also some Baby/Children yard sales on FB; you may find some in there too.
I have a friend who is a school teacher, and she can buy some books for me on Scholastic with a special discount for teachers too.
Half Price Books, if it exists in your area (I think they cover most if not all of USA) have a children's foreign language section. Even in the middle of monolingual Iowa I managed to find quite a few Spanish books there. It's usually right next to the kid's section, and separate for the adult foreign language section.
You could also try to exchange books with other bilingual families you know. I have mentioned this to my friends but so far we haven't got around to doing it. Books are fairly expensive in Spain plus they often tend to sell hardbacks (which are more expensive). I don't think half price bookshops exist and where I live there aren't any second hand bookshops...but try secondhand bookshops and charity shops too. I got my books mainly from Amazon as where I live there is little choice in minority language books especially children's and they are more expensive but am also starting to look at Ebay. Are there any other UK online discount bookshops that I could order books from? Even starting to consider buying a Kindle/Ebook as you can download many books cheaper (although I prefer the traditional books!).
Also, if your children are young and can't read yet, you can just use your English books you have and translate or make up the story in Spanish. It's just about them hearing the story in Spanish and the pictures helping them to understand what's going on and learning new words. Sometimes I shorten stories when reading in English to the kids...but of course I get caught out sometimes lol. My daughter is like, hey, you skipped when X, Y, Z happened!
Mayken: Adam Beck, thanks for sharing the impressions of your trip to China! I love those duck boats and that doorway! And meeting those kids wanting to speak English with you is so amazing!(I won't enter the giveaway because I'm afraid of winning the chicken claws!)
Feb 6, 2019 0:24:50 GMT 9
Mayken: My friend S asked her bilingual 2.5-year-old daughter: What language do mommy & daddy speak? D: English! S: What language does Grandma speak? D: French! S: What language do the cats speak? D (*thinks, then answers*): Meow!
Feb 7, 2019 0:08:00 GMT 9
Amy: Bless!! how cute is that!!! Reminds me of a similar thing that happened with my youngest when she was 18 months: she said the sound right for every animal but the cow. She kept answering "Lola" because of a famous Spanish nursery rhyme about a cow!
Feb 7, 2019 0:40:09 GMT 9
Alba: My son caught us by surprise when we said thank you (in English) to a waiter in a Mexican restaurant, and he said "gracias" (thank you) to him too in Spanish, also signing it! He was having a blast and there was some Spanish music in the background.
Feb 10, 2019 18:48:58 GMT 9
Adam Beck: Sounds like a wonderful moment, Alba!
Feb 11, 2019 11:57:53 GMT 9
Alba: Streaming problems: I decided to play some cartoons in ml2 (Hindi) which I knew had been playing in ml2 the day before with his dad. I was studying my son's face to see if he understood, turns out the cartoon was in Polish, not sure why!
Apr 4, 2019 0:44:39 GMT 9
Amy: Cute code switching this morning when my 3 year old told me "I get my pótamo" (she meant her hippo soft toy). This mixing was music to my ears... It means she is truly growing trilingual.
Apr 6, 2019 2:51:35 GMT 9
Adam Beck: Lovely, Amy! Good for you, and good for her! P.S. I like hippos.
Apr 7, 2019 10:32:37 GMT 9
Alba: So funny, Amy! Great to hear I love the word Hypo, every child says it different! My son did something similar when he say "This tocotó", he calls horses "tocotó" based on the noise they made when trotting (tocotó, iiii (neigh)-ok, for a Spanish ear)
Apr 8, 2019 6:52:09 GMT 9
Amy: Cheer Alba and Adam Beck! . I love these "baby" words. They are so cute. I like the "This tocotó" another example of state of the art Spanglish <3
Apr 9, 2019 4:54:05 GMT 9