According to this article, former Presidents and their spouses get lifetime Secret Service protection, as well as their offspring up to age 16. Former Presidents can also get up to $1 million per year in travel expenses and their spouses $500,000 per year. Of course, at the rate Obama is going it seems he would be exceeding these limits.
https://thepointsguy.com/2017/02/how-former-presidents-fly/
Right now, there are of course 5 former Presidents and their spouses still living under Secret Service protection (Carter, Bush Sr, Clinton, Bush Jr, Obama).
“..Former Presidents can also get up to $1 million per year in travel expenses and their spouses $500,000 per year.”
How about Congress passing legislation reducing the lavishness of past-president’s perks. Maybe along the lines of what Truman received.