It all depends on the level of performance you need
If you need something in the .30-06 performance class, you have to accept the expense.
You can get yourself around with a moped, but when you need a pickuptruck, you have to pony up the money for it, and the expense to run it. Nothing else will do.
If you are only interested in shooting paper at short (100 yards and under) ranges, a .22 is fine. .22 rimfire is the cheapest ammo that exists. If you want something more (more bullet weight, more speed, more energy, more range), the cost goes up dramatically.
Take a good look at that .30-06 round, and figure out how many .22RF rounds could have been made out of the same amount of material. 10? 12? 15? Think about it. The bullet is more than 300% heavier, and moving about 250% faster.
More performance means more cost, in everything. And it is not linear. Sometimes you pay a little more for much improved performance, and sometimes you pay a lot for slightly improved performance. It all depends on exactly what kind of item you are talking about. A 10" TV will cost you under $100, but that 50" big screen will cost you a few thousand. Economy cars are cheaper than sports cars or big SUVs. Everything has a cost, and nowdays, that cost has gone (and is still going) up.
If all you want to do is punch paper, and you want more than a .22LR, but want to keep the ammo costs down, the next common step up is the .223/5.56mm round. If you learn handloading, you can cut the cost of ammo even more, once you get past the cost of the tools.