I think a site can be ugly and still sell as long as the more important factors are there (some of which have been touched on here already)
1. Speed and ease of customer journey
2. trust - if the site looks trustworthy, phone numbers, reviews, etc people will buy even if ugly.
3. Target market, product and competition
4. Quality of product images
However, I think a better looking site with more conversion points that specifically targets your market will sell better in most circumstances, therefore it is all relative to your customer and competition.
(edited as I forgot this was public)
1. Speed and ease of customer journey
2. trust - if the site looks trustworthy, phone numbers, reviews, etc people will buy even if ugly.
3. Target market, product and competition
4. Quality of product images
However, I think a better looking site with more conversion points that specifically targets your market will sell better in most circumstances, therefore it is all relative to your customer and competition.
(edited as I forgot this was public)

not quite sure how he thought he would get away with it!