Link exchange (aka affiliate marketing) is still a very disputable question for most businesses. While it is officially admitted that the more links from similar/relevant websites lead to your website- the better you rank in Google, you do not want to look unprofessional by posting the return links to everyone in the world offering to check out your partners’ products and services.
The basic idea behind affiliate marketing is re-presenting your partners’products or services on your platform and receiving a bonus (a fixed sum, or a %) for any visitor/sale that came through you.
To help businesses manage their affiliate marketing there exists special software (here is the rank of options by Search Engine Journal) as well as affiliate networks (like eBay Partner Network or ShareASale). For loads of other names you can just Google affiliate networks and explore the results.
But it is all not too straightforward, unfortunately. You also have to take into account the subjective factor of relationships. The better relationship – the better position for your product showcase and at a better rate (or no rate at all). So you need to invest time and effort into developing your affiliate network before it starts earning you bucks.
In my work now I showcase our suppliers on our website. This is actually what our business is about- distribution. They manufacture, we bring in and sell. Most of our partners trade in Australia through us exclusively, that is why I do not see a problem in just linking our websites, like I did with one of our products SIBU. I saved a lot of effort and time by copy-pasting the description and linking it to the relevant page on their website. This is not ideal in the long perspective, but works really good in my current situation when resources are gold.