The Prime Minister of Samoa (who also happens to be the country's rugby president) has announced the SRU are bankrupt, and asking for public donations and 'goodwill gestures' from their European tour opponents. Don't know how they got to that point but you'd have to assume something went ridiculously wrong, either through World Rugby not giving them enough and/or Samoan officials running off with it.
Or a 3rd option of extremely bad organisation, whatever it was how does a team that's qualified for the World Cup on all but the first tournament manage to run out of money?
Having not looked into this at all, my naive guess is that they play all their matches away from home and thus haven't managed to negotiate a good enough share of the gate & TV receipts to cover the cost of running the team, flying and accommodating the players etc. Also, in rugby it is easier to change national teams so the best Samoan players don't play for Samoa, again affecting their marketing ability to negotiate.
Or they have bad management.