A cheapo dollar store socket and wrench set will work fine for you until you can afford a better set.
If you do the following it will void your warranty.
Choose wisely.
Besids your screwdriver, you will need 2 crescent wrenches and the spark plug tool that came with your kit.
1. Remove gear case cover.
2. Using spark plug tool, determine which end of it fits the nut in the center of the small gear. Remove nut from center of small gear.
3. Pick out toothed lock washer from center of gear if it did not come out with the nut.
4. Be sure threads cut into the recess of the little gear are clean from debris.
5. Be sure threads on little tool are clean from debris.
6. Unscrew center screw from little tool.
7. Be sure that threads on center screw that you unscrewed from the little tool are well lubricated. The factory oil is only there to prevent corrosion, it is a lousy lubricant, do not rely on it. (Use engine oil, axle grease, bacon fat, lard, anything but the factory applied anti corrosion oil.)
8. One end of the tool will fit into the threads cut into the recess of the small gear.
Determine the best fitting end. Thread the tool into the small gear straight and true. Be very careful as it will easily cross thread.
Keep turning the puller tool until it bottoms out. That should take up about half of the available threads on the little tool. If it is only threaded on 2 or 3 threads, it is not enough., If you try to use the tool that way you will only bugger up the threads as the tool slips out under pressure. It should go all the way in with finger pressure, no wrench needed. If not, carefully use a wrench to seat it all the way in. It does not need to be tightened very tight at all, just threaded in deeply.
9. Hold the tool with a crescent wrench adjusted to tightly fit the flat sides of the tool. Do not let the tool turn during the following procedures.
10. Screw in the now lubricated center screw that you previously removed from the tool.
When the center screw gets tight, use the other crescent wrench to tighten it further. Keep turning it. The gear should slide right off of the end of the shaft.
11. There will be a small half moon shaped piece of metal in there as well.
It is called a woodruff key. It fits into a notch cut into the shaft and a groove cut into the hole in the center of the gear. Be careful not to loose it as they have a habit of dropping on the floor and getting lost.
12. Now, you should be able to pedal the bike around with the clutch engaged as the clutch is disconnected from the engine's crankshaft. If not, then the problem is not inside the engine, but in the clutch shaft/ clutch spring/ bearing (s) assembly.