Amberly Grant traveled and camped across Scotland to save on accommodations.Courtesy of Amberly GrantAmberly Grant achieved 'coast FIRE' by saving 75% of her income and investing in index funds.For years, she lived on $1,300 a month by saving big on housing and transportation.She used her savings to max out her 401(k) plan, Roth IRA, and HSA.For years, Amberly Grant didn't earn enough money to save for her future.At 19, she left the small Canadian town she grew up in and spent years traveling and working odd jobs."I've cleaned houses, walked dogs, worked in bars and restaurants; I've taught English in Thailand, and I've helped a friend with a nutrition and pilates studio in Sydney," Grant told Business Insider.