Get a good enough build for your toon. And I'd say don't bother with L15 common IOs for leveling. Find a way to level to 22. Only slot for Accuracy and little else, with what drops and avoid buying. Keep the salvage and recipes (having your own SG base and its storage helps here), sell the enhancements and at low level even inspirations to get an Influence float. 4 Death-From-Below's and some teaming will do it. Maybe a Positron TF #1 and #2, maybe a Synapse.
Once you're level 22, take the Invention arc in either Steel Canyon or Cap Au Diablo and get a L25 Accuracy IO. Then craft enough common L25 IOs to slot your toon. If you'd running more than one alt, share the salvage and recipes (again a personal SG base helps) on one crafter. Have the crafter do enough L25 and L30 IOs to get those Invention Badges, as it increases your Invention salvage capacity and makes L25 IOs cheaper to craft (no recipes needed).
Buy the recipes and the common and uncommon salvage you need but don't have off of the Auction House, but be sure to limit this to what you really need at this point. You're not crafting for a great build right now, just a good enough one to continue leveling. Don't find the buy-now price at the Auction House, put in a lower bid and wait. Avoid buying rare salvage. Craft some high priced IOs and sell them to finance things. Accumulate an Influence float so you can afford to post the stuff to sell at the Auction House for a good value and not just 1 to get whoever has the highest bid right now.
Continue using L25 common IOs until you get to 50. Then think about accumulating the fancy IOs to slot the build then. Lots more detail to how to do things well, but this is a start.
Final builds for a level 50 are complex. They should allow for some exemplaring, as you will be running task forces. Also, be careful how you spend Reward Merits, special Enhancement salvage, and Empies once you get to 50. There are a few best ways to use them and many that are a waste. Learn the better ways.