I'm going to give you a personal opinion here.
First, the cost of the officiate is one of the smallest costs of most weddings. During the wedding all eyes will be on three people....the bride....the groom....and the officiate. Why anyone would put an amateur in this important position to save a little money is beyond me.
A wedding is an event that marks one of the most significant moments in the life of a couple, Why would you give the job of creating a performing that ceremony to someone not experienced at planning and officiating weddings?
Another issue to consider with an amateur. In the last several years a Pennsylvania couple got married using a friend who got ordained on the net so he could be their wedding officiate. Sadly the marriage didn't work and in the divorce one party argued that the marriage was not valid at all, as the friend officiate "wasn't really a minister.."
A few of the cancelling ministers were from wedding companies. I started to write professional wedding companies, but obviously these folks were not very professional .
A professional will give you a contract. And that means they will show up for your wedding. And if they become ill or have some other issue, the professional will always have a backup plan.
Since 1993 we have never cancelled or missed a wedding date. And we have four available ministers, so if one of us is ill, we have backup.
Doesn't that all sound like a better idea that asking an amateur or a less professional wedding ministers?