As a seller and frequent buyer on this platform, the #1 tip I can give y’all is to not be a weasel with pricing.
If someone says that because you have specific requirements that will take extra time and work, trust them on that. Don’t try to argue that the job really isn’t as hard as the (most likely experienced) seller thinks it is or reduce and expect and extreme price reduction.
Sellers work at highly discounted rates here on Fiverr, so you’re already getting a steal. Either you can afford the steal or you can’t. It’s not a sellers job to help you afford things.
BONUS: Sellers who are also buyers, don’t try to weasel other sellers into prices cheaper than your own. (Ex: Trying to get 3k for $5 when you charge $85)