@Slavijana *********
Actually, SOME embassies are asking to upload into the E-Visa application a proof of funds of a minimum of 20,000 THB or equivalent, in your home bank account.
Here is an example of the requirements for the application to a single entry tourist visa by the Royal Thai Embassy in Vienna.
It might be similar in your home country, or in the home country of the OP, which is Sweden
You can get asked for proof of cash equivalent of 20,000 THB or equivalent in another major currency by the Immigration upon entering Thailand. However, this rarely happens. They only ask it from people if they want to find a reason to deny entry.
You can also get asked to prove that you have a minimum of equivalent of 20,000 THB (600 U.S. Dollars) on your home bank account when applying for a visa through the E-Visa online system. Here is the bank statement requirement from the Thai Embassy Vienna. NOTE: this is up to date and actually gets requested (some people accused me of posting old and obsolete information!)