I have also turned into a Fiverr seller for the last few months who works on quality more than anything else and care about every client/customer of mine. But I see many gigs which just makes me burst out in laughter and also make me feel sorry for the buyers of those gigs. Some of the top sellers on Fiverr sell Scrapebox blasts of 40,000 directly to the money sites as being being Google Penguin, Panda, Hummingbird and what not passed. They just plainly without any empathy for their customers or their websites.
So, always be sure of apply logic before purchasing any gig on Fiverr. I openly tell my customers not to buy a gig from me if I personally feel that probably they would not be benefited from my gig. I always put ethics above money in case of any transaction. But 90% of Fiverr buyers are exactly the opposite of who I am from what I have seen (I have been been a buyer for over 4 years before turning into a seller too). As a thumb rule, if it sounds too good to be true, then probably it is too good to be true.
A $5 permanent link on a genuine high quality website is almost impossible to find genuinely unless it is an expired domain. But then you need to check the PA, CF/TF etc. instead of just the PR while purchasing links. I have hundreds of domains and have a lot of PR 5, PR 6 which I keep on finding at times. If I just post some articles on an expired PR 5 domain (which is bought at a registration price of say $10) and then I start selling links as PR 5 homepage links on Fiverr, would it make sense? Literally speaking, it would but ethically speaking probably not. But the links might still hold value but the problem with Fiverr both PBN and guest post links is that those links are shared with probably hundreds of other orders. So, they are visible to anyone ordering the gig including the gig and can be one of the easiest target for facing a manual penalty from Google.
Unless you are using them for a churn and burn site (where it might work ok), I would personally not advise to go for such gigs.