In my personal experience, unless I'm the first off the tee on Saturday morning, it's going to be the slowest round I play all week.
I play a wide range of golf courses, depending on where I'm at, who I'm playing with, etc.
I take clients and colleagues out several times per year, and we usually hit top 100 courses. Not really any way to save on these other than playing in the shoulder seasons.
Other times, when I'm looking to just log a round in, I'll employ a few strategies. One is to use the online booking sites, where I usually just pick the best bang for my buck. Sometimes I can get really lucky, like last week when I found a tee time for a single for Sunday morning listed at $0.00. Paid the 2 dollar trans fee, thought I might have trouble getting the course to honor it, but no problems. $50 round for $2.00!
I'll also try to find some go to twilight courses to hit after work. If the course is wide open I can usually get in 27 holes if I'm by myself.
Also I've found there's almost always 2 for 1 coupons to be had, which keeps rounds around 25 bucks each for 2.
There's also a few courses that offer free greens fees for your birthday, and if your birthday falls in the offseason (like mine) you just have to use it by July, which gives me about 5-6 free rounds a year.
I've done the punch card thing that gives you rounds at 8 courses for cheap, but I've found that I don't save that much because I don't end up traveling to the more distant courses that are dog tracks, because I'd spend more in gas than it's worth for the free round.
I've also tried to find memberships, but they're so overpriced in my area, especially for the quality of courses. Also given that I travel a lot, I'd have a hard time getting my money's worth. There is a couple courses that offer twilight memberships for $500 for unlimited golf after 3. Not bad, but I wouldn't do much better than break even on that, and I'd rather be able to switch it up now and then.
Also I like GroupGolfer.com, they get some pretty solid deals on there, especially for some of the resorts up north in my state.
Kind of a long winded answer, but there are lots of places to find cheap golf. There are so few marginal costs for a golf course that they'll cut deals all the time. Just have to look out for them.