I'd certainly defer to the 150 owners in the crowd if they choose to pipe up, but $60/hr wet means...
$5/gal for fuel (roughly... Use your own local number) * 9 gal/hr = $45/hr.
60/hr - 45/hr =
... the aircraft operator only has $15/hr for maintenance and insurance.
I don't want to discourage you, but at least do the math and go in eyes-wide-open to the numbers.
$15/hr isn't a whole lot of money to keep it airworthy with current parts prices and mechanic's rates. A good mechanic around here (in a so-called big city, lower perhaps in rural areas) runs about $75/hr. Maybe $50 if you're damn lucky.
That 150 has to fly more than four hours just to pay the mechanic for one hour's labor, no parts/materials included.
That sounds okay at first since typically it'll go the full 100 hours between mandatory inspections with hopefully only minor things done to it, and of course hopefully the inspection finds nothing seriously amis. They're pretty simple birds without a ton to go wrong.
How long should a C-150 100 hour inspection take, by the book? I'll have to leave that one to the mechanics here.
Now add some of the known fixed costs in, and that $15 looks awfully sparse.
I don't know what an overhaul is running on an O-200 these days, but you can find that and plug that into the price also and know within a couple of bucks an hour how much is going into the engine replacement fund.
Let's see... A quick Google search says $18,000. That divides nicely into the 1800 hour TBO, so let's just say it takes $10/hr to pay for the required engine overhaul. That's an easy to use round-number for just double-checking the rental rate.
So we're now up to $55/hr for fuel and engine overhaul before we've even done anything to the aircraft or used it.
No insurance, no oil, no filters, no brake pads, no tires, nothing else. Just fuel and an engine fund.
You've got $5 hour left to pay for all of that at $60/hr.
Frankly, I think you need to be seeing about $65/hr-$70/hr as a bare minimum to keep a 150 properly maintained and fed with engine reserves. Parked outdoors. Hangar extra.
At $60/hr, that's a money-loser for someone. You're getting a screaming deal, if they're actually doing maintenance properly, because someone else is paying for the time you're flying off of the engine.
But that screaming deal may be skewing your perception of how "expensive" the newer 172s are.
With students flying that 150, complete with blown tires and flat spots, and the additional wear and tear of hard landings and general inability to be "kind" to it, I'd say a 150/152 normally would rent for a minimum $75/hr in today's market.
Now for fun lets see how close I got...
This article claims $85/hr is typical. Just a Google search... plus the article has an interesting premise. Haven't thought the author's questions through yet, but it'll make folks think at least.
http://www.airplaneflyingpilot.com/2010/12/why-cessna-150-and-152s-are-not-rented-as-much.html
So a quick scroll through Google results for C-150 rental rates yielded only one that said $70/hr. On closer inspection it had a $5 fuel surcharge in addition to the $70, so it was really $75/hr wet. Everything else was $85-$89/hr.
Run some numbers as if you owned it to see if there's warning signs that MX could be skimpy.
My quick numbers (you can plug in more accurate ones for your home area) say that $60/hr just isn't realistic for a flight school based C-150, IMHO.
Just out of curiosity... Does the club own the aircraft, or is it a leaseback? I've seen owners lose money on leasebacks just to lose LESS money than letting the engine and airframe corrode and die if they can't fly it enough. Those same owners sometimes really cheap-out on MX.
So... be careful. Think about what your $60/hr has to cover for the rental place to make it break even or a tiny profit.