Hi Jimmy and welcome to the forums.
Just a couple of points here;
1) If you're just using doing firelighting practice, get someone who knows a thing or two to show you some pointers. When I started out many years ago I would get hugely frustrated (and still do) by seeing perfectly healthy trees cut down because people weren't aware that burning wood "green" generally doesn't work! (With a few exceptions you will pick up in time). Oliver Rackham (well-known woodland historian) once said that "Native English woodland burns like wet asbestos!" Likewise if you are careful and considerate most landowners won't mind too much if you're just using a bit of deadwood to have a small fire (just be sure to get permission if you can). People generally object (and make life more difficult for the rest of us) when folk make huge fires, cut down a bunch of trees leaving ugly stumps and half-scorched logs strewn around, and otherwise show no consideration or respect for the land or those using it.
2) Try and keep any fire you have small in size; as the addage goes: "White man makes big fire, keeps warm looking for wood. Red man makes small fire, keeps warm". Moreover anyone coming across you will be much more likely to see that you're not just making a big burning mess and be much more sympathetic.
3) If you're looking for wood to burn at home, yes, I'm afraid it's more expensive than it was depending on where you are, so keep a lookout for local suppliers (people often advertise at the side of a road on a hand-painted sign). A good thing to do is while you're out and about keep an eye out for any roadside clearance or tree work going on. Quite often people clearing "problem" trees will let you take some for a small cost or even for nothing if you ask them nicely.
Hope this helps
