Numbers can be tricky things. On the one hand, they are quite clear about what will happen. On the other hand, there are things that can be left out of that so as to tell an incomplete story.
I'll take Sanders as an example, since he'd be the one of the 4 I'd vote for if I could pick. Let's say I earn $55,000 a year. According to the study done there, I would have a total change to my paycheck - for the year - of $3852.16. Okay, so I'm taking home $4000 less every year in pay.
One of the things that Bernie has promised is free healthcare to all Americans. No more needing to pay health insurance premiums, it would be (I imagine) a single-payer system (which is what we should have had instead of what we got) like the UK's NHS. Right now, I pay about $370 a month for my break-your-arm insurance plan. (And before you ask, no, it's not an Obamacare plan.) So, if I don't have to pay that every month, that means I'm saved a cost of $4,440 a year.
So in that deal, I actually gain about $500 a year, even though I'm technically earning less, because I'm saved an expense.
Let's say Bernie isn't going for free healthcare, though. BUT he promises free collegiate education to anyone who can get in. According to College Data, the average cost in tuition and fees for someone in-state attending a public university is $9,410 a year, for a grand total of $37,640 for a 4-year education. Let's say I have two kids to send to school - that number becomes $75,280. Dividing this cost by the loss of money to my paycheck each year, I get a total of 19.5 years. IE, the time it takes one of my kids to grow up. So I basically pay in taxes for both of my kids to go to school.
But the difference? When they walk out of college, degree in hand, there is no debt for either of them. Student debt is over a trillion and a half dollars now - outstripping even credit card debt - and unlike most forms of debt, declaring bankruptcy doesn't absolve you of it. On top of that, consider this - my example uses students attending a public school, in-state. If my kids want to go to a private school, or to a public university out-of-state? Then again, I actually save money.
Numbers are important.
But it's important to consider what you are getting...and what you are giving up in exchange for it. I don't know specifically about the Donald, but I know Cruz wants to really cut back on government programs. Are you willing to get that extra hundred dollars a month, if it means giving up food stamps?