Those old "suitcase" record players from the 60s will play 78s as well as standard vinyls. There's a mini-industry in refurbished ones - check Ebay for Fidelity, HMV, Bush etc - or my favourite, the square Dansette Bermuda. You're looking at circa £100 for a refurb, less for just a regular old player.

I think you need to be careful about buying modern decks which spin at 78. I remember reading that vinyl records have the music etched onto the sides of the groove, whereas 78s have it on the bottom, so the needle moves up and down as it plays, rather than left/right. Not sure if modern decks account for that.