Tithing

I have often heard others excuse financially unstable people (such as college students) from giving 10 percent to the church. By not tithing today they are possibly avoiding debt (also a biblical principle) and can make up for lack of tithing once stable.  Especially under tighter financial circumstances, should tithing 10 percent be a guideline we still follow, or should we only be obligated to give to the general fund as much as our church budgets?  It might surprise some readers to learn...