In what order would you do this?

The vendors are small niche/boutiques selling specialised goods. None are part of any affiliate programme/network and do not have any tracking software on their websites as it would cost too much for them to implement something like this. They are happy to use word-of-mouth agents and give them 10% cut on each sale but the agent has to collect the money from the customer then place the order, then once it arrives give/post it to the customer. Not efficient and makes no sense to the customer unless the agent gives them a 5% discount or something. Returns are tricky this way too.

When I approached few of them about online tracking - they rolled their eyes - its just too technical for them. Thing is, the big boys (who have affiliate programmes) HAVE clocked on the market and taking the customers away from them, but the small vendors have their heads stuck in the sand and don't really understand why.

I am planning to charge these small vendors a set monthly fee to have their products listed. I found a cheapish off the shelf WP price comparison theme where the products are loaded using CSV file. So each subscribing vendor will send me the file of products they want to list and i upload it manually. Once I have enough money in, I will invest into a more automated solution.

I am very excited about this but also worried because I have no idea what i am doing. I know the industry and products in question inside out, have done project management for software projects but learning about marketing and affiliates as i go along.

Mostly they are nice, decent people and I do realise this is not a solid basis for a business decision. I think that once they see more quality traffic to their site (through me) and more sales they will see the light. Thing is the industry is growing, more products are being launched, more people are buying. Before its was mainly sophisticated/niche customers but now more mainstream customers want a piece too. The products are also undergoing a bit of sex-ing up from models and celebrities. So, I see the potential, know many vendors personally and can influence them.

I dont think it will be a cake walk but i do see a potencial. It won't earn me millions but i dont need it to be. I would be happy with a 2-3 hundred a month, tbh. This industry is something I know well, have influence in and genuinely believe in the products. Being a vendor takes a lot of time but what i am trying to do here is to earn less than when i was a vendor but passively.
My long term plan is to sell the working site to someone in the industry who it will be worth more as part of their empire rather than a stand alone project and then re-invest the money into something else which generate more cash per month.

I do appreciate your feedback and questioning my logic in this, that's why i am posting here.

100 or so to start off with but new brands are coming up all the time, had to tell just how big the market will end up. Amazon store is and isn't a good solution for this. Hard to explain because that's where the industry knowledge come in handy.

Thank you all for advice, much work ahead for me then

Interesting, thank you. I need to think this over if this plan would fit the industry, as it's a unique market.