might as well discuss about it since it's gonna be patched any day most likely (rumor has it that the game devs know the method), lets at least try to find it out in the meantime
Done via external program/script or of some sort - CONFIRMED, CATCHME HAS A CUSTOM PROGRAM THAT HE USES TO DO THIS. BUT THE PROGRAM I AM USING AS SEEN IN THE PICTURE IS BASICALLY WHAT HIS DOES
EDIT: NOTE TO KEEP IN MIND: ALL ACCOUNTS HAVE BEGINNER PACKAGE BOUGHT ON THEM, I KNOW THAT THE BEGINNER PACKAGE WAS A VERY BIG PART OF THE LAST GOLD EXPLOIT, NOT SURE ABOUT THIS ONE THOUGH, MIGHT JUST ONLY HAVE BEGINNER PACKAGE ON ALL OF THEM SINCE ON A FRESH ACCOUNT IF YOU HAVE MORE THAN $20 WORTH OF GOLD THE BEGINNER PACKAGE IS AUTOMATICALLY APPLIED
my idea of how it works:
the $5 package is bought and they tamper the request mid-way so you change the value to 16,000 instead of 500 so that your account is given 16,000 gold instead (the external program is how you change the value)
(maybe only 16,000 is the highest u can do since the game possibly might be programmed to only give out sets of 500, 1200, 2600, 7000, 16000 gold since those are the in-game purchase amounts)
and you can only do it a couple times (5 times max, which would be 80k gold, assuming so since thats highest amount i see on the gold accounts being sold) before the account gets auto banned or something like that?
hence why
1) all gold accounts sold on mpgh are always have 16k, 32k, 48k, 64k, 80k
2) highest gold account sold on mpgh always has 80k gold
3) the price is higher for higher gold amount accounts since to make an 80k account using this (correct?) method it would cost $25
but to make a 16k account it would only cost $5, and well they obviously need profit, if it only cost $5 to do 80k on an account, i doubt
they would be so greedy to want so much for it considering that means it costs the same to make a 16k account and sell those for like $10

found the value 500 (edited it to 16000 as seen in pic) while tampering the request here (request is blocked and keeps attempting until "ok" is hit, so it gives you plenty of time to edit needed values or mess around with stuff) but i am virtually broke so didnt have $5 to invest:P