You could climb down into the canyon, camp on the way, and try to climb back out the next day. You can take a donkey ride partway down and back up the same day. You can take a float trip and ride a raft through the canyon, one of the ultimate adventure trips, from one night to as long as two weeks on the river. About $1500 to $4000 per person, depending on type of trip.
If you just want to take a look over the edge, that can be 2-3 hours in the busy part of the season, if you want to see how it looks from several different points on the south rim. That's enough for most visitors to most of the locations in the National Park system, checking off a "must see" list with their been there, done that. That's the typical bus tour visit, drive through, stop in two or three places to let everyone out to take pictures of themselves at the Grand Canyon.
That's as far as I've gotten with the Grand Canyon so far, a day trip out of Phoenix with wife, two kids, wife's aunt and uncle. I do intend to go back, stay longer, explore more of the park. But for stuff to do, different things to see, the Grand Canyon is not really the natural wonderland you will find at Yellowstone or Yosemite.
For that matter, I prefer Canyonlands NP to Grand Canyon NP, because there is a lot more geology to see. The canyons are just not as deep. If looking for water recreation activities (besides float trips) I suggest downstream to the National Recreation Area at Lake Mead, or upstream to the Glen Canyon NRA.
It doesn't necessarily cost $25 to have a look. Interagency pass to all Federal parks and monuments is $80 a year, visit 8 places on one trip and they only cost $10 each. Visit 20 they only cost $4 each. I bought the annual pass the year I retired, used it for at least thirty different places traveling that first year.
If someone in your party is age 62 or older they can buy a lifetime America the Beautiful Senior Pass for one-time fee ($10 the year I bought mine). It covers everyone in the vehicle with them.