I don't know about where you all come from, but here in the UK we only really have 2 main spots to put credit on our phone, a PayPoint or PayZone.
I used to pay by TXT, but now i use PayPoint. Firstly:

1.Go to www.cabalonline.com
2.Log in
3.Click Buy Cash
4.Choose your desired amount
5.Click PayByCash
6.Click Continue to paybycash.com
7.Select PayPoint payment method
8.Enter your details and click continue
9.Click the button to go to your paypoint statement
10.Print the paypoint statement
11.Bring it to your nearest Paypoint location, give the statement to the person behind the till, and say that you would like to pay for this through the paypoint.
12.He/She'll scan the barcode on the statement, and then you simply give her the exact amount that was allocated on your statement.
13.Cabal cash has been credited to your account.

I found this to be about 25% cheaper than the old SMS payment. Have fun