If you have time to wait, then you certainly can do so or you can pay couple bucks and get the functionality you need. It depends of the nature of your business if waiting months if not years saves more money then investing couple dollars/euros.
We´ve been building sites on osclass over 4 years and if we see a cool functionality needed for business you simply buy it, building it will costs you a lot more (working hours of developer are just more expensive). Also osclass gives you 99% of what you need to build a successful listing business, the last 1% is not free, you need to invest your time and money, to customize the platform for you specific business needs. I think that osclass market is the second best thing that happened to this platform, first one is that osclass team started building it and are giving it away for free.
The least you could do is to support core team by buying their plugins and also buy other developer plugins who are most of the times giving you more value for each plugin compare to their market price. But people and businesses are different, some expect a free superb experience to make money and others understand that you don´t build business without investing additional money and resource.