I've gone through almost this exact scenario. There's a couple key challenges you need to overcome early in your engagement with potential clients.
First, recognize you're not offering them something "for free." An integration with an ERP system takes man-hours, and I assume whatever your'e offering is going to require some level of investment, time or otherwise, on an ongoing basis so you'll have a hard time approaching businesses with a "free" pitch.
Second, if you lead with a $0 sticker price you immediately remove any value associated with your product and your brand, as well as any credibility that you'll actually be able to deliver. Your messaging needs to focus on what you'll deliver and how you'll do it.
What I would recommend would be to seek out your ideal customers and approach them, with confidence, as an established brand that can deliver exactly what you're promising with a price tag to match. Only after this point, when you're negotiating the details of your deal, should you offer discounts to drive the deal to the finish line.