PayVeX is Open Source, licensed under the GPL, version 2
PayVeX ships with the source code, you are free to modify it or run it on as many computers as you see fit. Furthermore, you are free to distribute copies as you see fit (provided they are compliant with the GPL)
Source gnu.org: Selling Free Software
Since free software is not a matter of price, a low price isn't more free, or closer to free. So if you are redistributing copies of free software, you might as well charge a substantial fee and make some money. Redistributing free software is a good and legitimate activity; if you do it, you might as well make a profit from it.
In recent years, people have been observed referring to free software (more accurately named open source) as "freeware". This is unfortunate, as it completely dilutes the true value of having access to the source code (rightfully yours I might add) for any software package you have purchased.
The failure to convey the most valuable aspect of open source has led to a general devaluation of open source software. Rather than see its true value, people have become accustomed to seeing it as "freeware".
If you design free, open source software we urge you to charge for it, you will be helping the open source movement in many ways. The current, popular model is not sustainable, results in the dilution of the true value of open source, promotes a massive mis-understanding and will eventually result in failure.
If you design GPL software, we will help you in any way possible to sell your project under the GPL license.
Remember, the real goal is to promote that freedom has a value and NO that isn't pointless. Sure, there are people who will just use a copy but there are others who will want to ensure they get an unmodified copy directly from you.
Furthermore, you will be promoting friendships as some people may elect to pool their resources and collectively purchase a copy from you, this in itself is certainly worth something!