Indians Satya Ranjan Sen and U.B. Mayood, both 62, are trying to prove to their friends and people they have met during their bicycle trip through Thailand, Laos, Cambodia, and Viet Nam that money is not a factor in travelling and enjoying nature.
With just 50,000 rupees (US$800) in their pockets, the two retired men from Kolkata and Bangalore have been cycling to cities and other popular destinations in the four countries for the last month.
Their message is universal brotherhood and protection of nature.
On arriving in HCM City from Ha Noi, Mayood told the media that they had met each other by chance while trekking in the Himalayas last year and decided to go on a trip with a limited budget.
Mayood goes trekking three times a year and said "this is a way to keep myself healthy."
"I don't want to sit at home after retiring.
"We can be healthy by doing this kind of activity and I want to tell people who are above 60 to go out and become healthy."
They have been visiting schools and colleges to encourage people to trek in the Himalayas.
"Money is not a criterion. Don't worry," Sen has been telling everybody he met.
They started by travelling to Bangkok from Kolkata on August 21 and have so far spent $450.
Asked how they can manage to travel on so little money, Sen said: "We put up a tent to sleep and cook ourselves. In the city we cannot do that, so we go to suburbs.
"If we go to a restaurant we have to spend VND50,000 ($2.4), but if we cook ourselves we only spend VND5,000."
"We are inviting you to visit India with this amount."
Mayood said: "Viet Nam is a very beautiful country with many rivers, but language is the biggest problem.
"We have met many friendly people. We understand their affection through their body language. That is enough for us."
In Ha Noi, they did not come across anyone who spoke English. They tried to ask everyone they met how to go to the sea, another of their favourite places, but in vain.
"Finally, we used a map to ask. We spent two days [at the beach]."
Today the two leave HCM City for Phnom Penh. Then they return to Bangkok for a few days before leaving for Kolkata on the 19th.