Would expect it to be a little more expensive than $30, averaging around $100.

@RayDoraisamy Hmm. I’ve found flights from Brazil to Uruguay for $81 so would expect a short bus route from a Brazilian border town to a neighboring country’s border town to be significantly cheaper. The websites for these little bus companies have proven unnavigable so far. 

@Charlie yeah, I had the same issue last year, ended up getting a ticket, but I was also crunched for time. I have a feeling that if you called a local bus company or something like that, you would have better luck finding that kind of price.

Best I could find was $60 for Pelotas to Punta del Este on https://www.clickbus.com.br/ :P

Also no one checked for proof of onward travel anyway 😢. 