Please help! What is the difference between an implant and bridgework. Which one is economical?

Bridge or Implant. Studies show that traditional bridges work but fail about 15-17 years after being placed about 35% of the time. Implants fail at about 3% at 17-20 years after placement. You decide. They cost about the same if you do not need site development. You decide.
Depends. Do you mean a fixed or permanent bridgework or remove able bridgework? A fixed bridge uses anchor teeth on either side of a space. An implant is a titanium screw placed into the bone to replace a missing tooth/teeth. Implants normally are normally more costly than bridgework but every case is different. Good luck.
Short v. Long term. You can google details. Short term, bridge may be slightly less costly. Implant is always more economical if you are young (>15 years to live!) because bridges fail biologically with decay. Think: what are you going to do in 12 years when it fails and you lose the tooth that it is attached to? Implant does not depend on other teeth. You need to think long term. Next decade is not that far away...