Generally, if a VPS is cheap it probably means that they don’t have much bandwidth. What you might want to consider doing is contacting the VPS provider (sending an email to their support email address, or contacting them via their contact tab on their website, and asking them how much bandwidth they are providing your account with and also ask weather they allow tor (and ask if they allow port forwarding).
Generally, bridges require less bandwidth then public relays do as they are mostly only used in areas where the tor network is blocked, whereas the public relays handle every bit of traffic sent through the network (from guard or bridge relays to exit nodes, and exit nodes back to guard or bridge relays).
Contact them (the vps provider) with these questions and tell us what they said. If you’d kindly provide us with the name of the VPS provide I’ll try to find some information.
Thank you.
From: I Sent: Monday, June 25, 2018 8:59 PM To: tor-relays@lists.torproject.org Subject: Re: [tor-relays] bridge installation help please
Thank you. There do seem to be a few faults and missing bits in the help stuff.
As nothing has worked I'll reinstall Deb9 and start again. I wonder whether cheap VPS operators might have something to do with the problems.
Rob