It may be negative but he may also be doing the OP a favour and saving them months and thousands trying to market and build a no goer. What many of you are missing is that this isn't even a supply site, it is a comparison site. Unfortunately the market you are in is extremely competitive and that is between the actual suppliers with more margin and repeat business value to attribute to their cost per customer acquisition calculations.
The OP has duplicated content therefore seo value is very low and will need to concentrate on marketing spend, facebook is hit and miss so no guarantees there. As it is a comparison site then even ppc would need to be constructed with more general terms.
Now for some basic maths, lets take the phrase Whey Protein for example. The suggested bid is £1.84 per click. At a average of 6% conversion rate, the cost per customer acquisition is over £30 on a £44.99 product tops, with what, an affiliate commission of 12.5%? Therefore net profit of £5.62, which means the op will need to sell over 5 units to break even or average retail spend would need to be around £250 per customer to make a little profit. As it is a comparison website, the user is new to the industry so not buying bulk and will likely buy one months supply to test it. As the average affiliate cookie lasts 30-35 days, the OP may get commission for the next sale but there is a chance they won't as many protein purchases are a months supply.
Therefore PPC is probably not going to be profitable. If you are looking for protein powder and don't know where to start, what is the first thing you do? Google it.
Therefore you are going to have to heavily invest in seo and content to be even in with a shot, bearing in mind the suppliers are doing the same thing, in a competitive market, with a large marketing budget. The OP could get very creative with their marketing and do some private advertising deals with companies serving their target market. However, the only problem here is that they are an affiliate so there is very little money in the pot to share and even then, there is the potential that their actual suppliers could come in, do the same deal and pay the company more as their margin is higher.
Sorry to say it but on the face of it, this one is a no goer unless you remodel the business plan from the ground up.