Three-time world champion Asbel Kiprop said he paid drugs testers because he "thought they wanted the money for fuel or tea".
Kiprop, who won 1500m gold at the 2008 Olympics in Beijing, tested positive for EPO out of competition in 2017.
The 28-year-old Kenyan alleged his sample "turned positive" because he did not give the testers enough money.
"It is rare for them to ask for money. They didn't specify the amount," Kiprop told BBC Sport.
"To me, I could trust them. It didn't even come into my mind that I was in a sensitive position."
Kiprop also said:
He was visited by the same testers three times that week
He would frequently be asked by testers to go to their houses to give samples
He would always be forewarned he was going to be tested, which is against anti-doping rules
He has since texted the testers to ask why they no longer test him themselves, and has received no reply
He "almost wishes" he had doped so that he could deal with the situation better
He believes dopers should serve a jail term
In May the Athletics Integrity Unit (AIU) rejected claims his sample was tampered with and that testers had asked him for money.
Kiprop was tested on 27 November 2017 in Iten, Kenya, having been told the previous night that doping control officers would be visiting.
Although that is against protocol, Kiprop said he did not take it as "something serious" because it had happened before.
The AIU said Kiprop's sample was not tampered with but said it is "extremely disappointing" he was given advance notice of the test.
He alleges a doping control officer - one of two present - asked for money before he had given a urine sample.
After supplying his sample, he left it unattended with the testers while he went to his bedroom to get his mobile phone, through which he paid them via electronic transfer.
"I have never violated the anti-doping rules or try to avoid the testers because I am sincere to myself and I support anti-doping," Kiprop said.
"I was so confident about my sample. I never even doubted myself.
"The minute I went into my room to send them the money, probably something happened there on the table to my urine sample."