The short answer is “it depends”.
While bridges and dentures may be less expensive at the outset, you should consider that both options have sometimes considerable continuing expenses. Bridges, by their structure, cut down the neighboring abutment teeth – which can lead to weakness and additional treatments (i.e. root canal treatment). Dentures cannot preserve the jaw bone the way dental implants can, so the jaw shrinks as the bone is resorbed, leading to ill-fitting dentures and repeated appointments of re-fitting and re-placement of the dentures. Over a lifetime, dental implants can be the cost-effective as well as the aesthetic choice.