I mean, whatever script you develop, there's of trillions of similar scripts on web, many of them free, with large communities, etc... I can count with the fingers of one hand the times I sold one of my scripts. Is there any way to make it profitable?
Reputation is everything. The more clients you work for, the bigger your portfolio. If your portfolio is big and attractive, you can attract better clients. There are millions of scripts out there, but think of them as "off the shelf" software. While this would be workable for many clients, some may want bespoke software which is where you would come in. Now, would you build the bespoke software from scratch? That depends, is there any existing software available? Is it workable? If yes, then you would use the existing software and build into it, or use your own libraries. Programming is a niche, a saturated niche but a niche nonetheless. Along with millions if scripts, there are millions upon millions of websites worldwide which all need maintaining, upgrading, built into, mobile sites built, tablet compatibility. Your question is probably not thought out very well, this is an exciting time for developers. With the latest smartphones, tablets and other devices, there's an unsaturated niche which is getting all of these millions of businesses to have a website that works on those devices. So yes, I believe there is money to be made in development.
Just put up your site with a neat design, SEO the hell out of it, or you can find exclusive script selling communities (websites) where you can sell your own scripts. That way you can increase your reputation! Just google it, and trust me, you WILL find it!
It's profitable, but it's a lot more work than bespoke work. You need to make sure your script works with lots of different server configs, you need to document everything and build a solid admin CP with lots of settings.