If you're just starting out, three power tools for general woodworking that are worth spending more money on include a good tablesaw, router and drill press. With these three, plus some hand tools, you will be able to build many of the projects in how-to magazines. Which tool you buy first can depend on the projects you are planning, but a good saw usually gets priority.
When staining your deck, be careful not to apply too much of the stain. You don’t want to get surface film on the wood when what you’re really going for is penetration. Also, be sure to keep a wet edge so you don’t get unsightly lap marks. Apply stain in the proper weather conditions. Avoid applying the product in direct sunlight, and be sure there is no chance of rain for the next 24 hours.