In English I might say thanks instead of thank you. In Portuguese I'd say valeu as an informal obrigado or, for a big thank you to a friend, you can also informally say obrigadão (the augmentative).
Does Spanish any similar, informal thank-yous? Perhaps regional or slang words.
I think that gracias is the most basic, standard way to say thank you in Spanish. If you want more options, you have to seek upwards:
Nonetheless, some of the more formal options can be exaggeratedly deformed for comical relief:
So, I'm afraid that in Spanish if you want more informal ways to say gracias you'll have to be a bit creative...
In Chile we also say "te pasaste" to thank and congratulate. But beware, because in other countries it probably means the opposite ("you have exceeded negatively").
Muy amable
(Mexico at least)
Sometimes this is used in conjunction with "gracias," but it can stand on its own if you have to or want to be especially succinct. For example, I was a bit disoriented when driving in a strange city recently, pulled over to ask a woman who was standing on the corner chatting on the phone, noticed she was speaking in Spanish on the phone, and asked her in Spanish if I should turn at that corner to get to the bus station. It was possible I might find that I was blocking traffic, so I only said, "Muy amable." Where the full version is "Gracias, muy amable," or "Gracias, señora, muy amable." (Roughly equivalent to "Thank you, you're an angel.") This is not slang, it's gracious speech that anyone can use comfortably. (Not that I have anything against slang, but you need to know what is and what isn't slang.)
Note: I forgot to include a literal translation of "muy amable": [That is] very kind [of you].
(Esto / Ud.) me ayudó mucho
This would work in any language. If you want to show your appreciation for something someone did, or information provided, and you don't want to repeat "thank you" for the umpteenth time, you could say (This / You) was very helpful [for me].
If Latin American slang is acceptable for your use case, in Chilean Spanish we use "vale" as a very informal "gracias".
Here in Mexico we sometimes use Chido that also means good, great or funny.
In certain areas in Mexico, it's common to express gratitude with enthusiasm, in a way that a word for thank you is not explicitly necessary. This would likely be the most vulgar way of saying thank you that is positive and acceptable among people, especially peers.
This is slang and language you would not use in a formal setting or with superiors, but among friends, if someone gives you a gift or brings you something you wanted (especially when it's hard to find or to acquire), you are able to use phrases that congratulate the person who has gotten you said gift for their ability to acquire it.
See, for example:
¡Wey, te la rifas, me encantan estas galletas!
(Here, te la rifas is regional slang for something akin to you're so badass)
Another answer said it before, but in order to say thank you in ways that are more vulgar than gracias, you'll have to be a special kind of creative.
Generally people in Latinamerica just say "Gracias" or "que Dios te lo pague, porque yo no puedo" (may God pay you because I don't have enough to pay for such a big favor) because you don't know how to give back the favor someone has done to you, or if someone has lent you money and you won't be able to give it back.
Another thing people can say is "Dios te bendiga" (God bless you) or "Me fue de mucha ayuda" (it helped me a lot).
Since the famous Argentine band Soda Stereo gave their last live concert in 1997, it's been rather common in Argentina to use the expression Gracias totales, employed by their late vocalist Gustavo Cerati (hear it at the end of this video or else here). It's definitely informal, but it's got the right vintage to sound at least familiar to almost everyone in Argentina, and possibly elsewhere (Soda Stereo was well-known in most of Latin America).
