I'm not sure if this will be a good suggestion for many of your readers, but I have had tremendous success with bonus credit cards. I just recently returned from 4 months in Asia and am about to embark on a 5 month trip to Europe, much of which is free because of the points I've accumulated.
Here's how it works:
There are several reward credit cards that offer really generous sign up bonuses. Among them are several Chase cards, airline affiliated cards and Capital One, Barclay, etc. They all have requirements to meet the bonus criteria, and some of them have annual fees, but the rewards far outweigh the costs if you travel a lot.
I accumulated 600,000 points in 5 months doing this, and I still have a long way to go using them....my airfare to Rome and many nights of accomodation along with car rental is already paid for.
I would suggest that your readers go to one of a couple of websites to check out the offers....there are links to each of them and your readers can decide which are the most relevant and cost effective.www.millionmilesecrets.comwww.doctorofcredit.comwww.onemileatatime.com
I am on an 18 month hiatus from art because I've wanted to do this travel thing my whole adult life! I rented out my condo and am almost 5 months into my nomadic year and a half. After Europe, it's Mexico and S. America!
I'll be back in the loop for the 2018 season!
Best to you and your readers,