Tubes are not quite as good as the other methods; slightly inferior to reversing the lens & a lot inferior to a dedicated macro lens, but they're straightforward, cheap & fun to experiment with.
There is very little in photography that can be done cheaply.

What are you hoping to photograph?
Because tubes reduce the amount of light[1] coming into the lens & also confuse the auto-focus mechanism, it makes it harder to focus on anything that might fly off before you're ready.

If your subjects will stay still, if you have additional light & if you don't mind a bit of trial & error, get a set of tubes. $£€ 35 or so will get you something quite acceptable. You want the ones with electronic contacts which will confuse your camera less. You can use them in any combination, depending on the length of your lens & how near you need to be.
There are some over 100 bucks - I cannot see why, all they are is a tube full of air.

If you're doing this in a controlled environment you might also invest in a macro rail for the top of your tripod [again, cheap on eBay, 20 bucks], so you can work on your multi-exposure focus stacking.

[1]Because maths: see elsewhere for proper scientific explanations

I'm pulling some comments into an answer, just by way of explanation Examples using a Tamron 70-300 with Macro function, vs Nikon 18-300 without any macro capability, vs a Nikon 50mm 1.4 and 36mm of extension tube [the largest from the pic above].
These are all rough, hand-held at the closest I could focus each time. No attempt at colour accuracy or any real consistency, just quick snaps by a partly sunny window for extra light.
This is a European 1 cent piece, btw, 16mm diameter, for those who don't recognise it.

Click for larger size [all are 1/3 original size, low-qual jpg for data saving]
Tamron 70-300 macro

Nikon 18-300

Nikon 50 with 36mm extension.
No infinity focus on this, of course.

Nikon 50mm can get closer/larger - but not if you're trying to photograph insects or anything that would spook. I was at about 5cm for the third shot, using my hand spanned between camera & floor to try keep still.
Note that the Tamron isn't a 'true' macro lens, it's a kind of compromise, but it does function reasonably well. I don't have a true macro lens for comparison.

For additional comparison, this is one I spent some time on, posted here before, a 2mm allium bud. This was done with the 50mm [idk exactly which tubes, with a 50mm lens the full 68mm of tubes focuses 'virtually' inside the lens, so you can't use all of them]