If you plan on forging alone/solo, you will literally need MILLIONS of NXT to have any chance of actually forging a block on your own. The most feasible way would be to join a forging pool by leasing your NXT balance to the pool and then receive a proportion of the rewards based on your on the percentage of coins you leased in regards to the total amount held by the pool. Even then, you need a fairly significant amount of NXT for it to be worthwhile, as you will spend at least 1 NXT just to send your lease, and then at least 1 more when you want your rewards sent to your wallet.

Hope that helps..