Creating one with the quality of OSCommerce will take me months.
That depends on whether you need all of the features. And whether you are
willing to put up with another vendor's tech support avenues. Or
integrating it into your site. Never mind what happens when you try to
integrate a "free" product (not only cost-free, but also support-free).
I need to
run one for many sites. I can't afford to buy many licenses.
Are these sites running e-commerce applications and not paying for them? If
you are developing for other clients, they should be able to absorb the
cost. And getting a site-wide license will probably be economical, too.
It is so disappointing to see e-commerce applications being stifled or
limited artificially because of the reluctance to spend the time, or the
money, or both, to do it right. Same with the component argument. People
are unwilling to spend $100 on an upload component but will spend two weeks
of their time developing their own buggy solution. But they saved money, I
guess, assuming their time is worthless. :-(