A few years ago, I was really keen on slide photography but didn't do much with them other than put them into a folder. I have been wanting to digitise them for ages, but kept putting it off, primarily due to the cost of the various provider who offer the service - basically between £100 and £200 for 100-300 photos dependent on quality and provider etc.
Recently though, I was looking through some old family photos (40-50 years old) - in truth these were not great quality slides, have been sitting in a cupboard for decades, but looking at them it's the memory I want to digitise more than the resolution.
Looking online I discovered that a modern DSLR and a macro lens (in my case a Canon 80D and a Sigma 105mm macro) combined with a light box (which I got for less than £40 off Amazon) can give pretty good results... rather than photograph the image via a projector you are photographing the slide itself... the camera resolution is good enough to let you do this, and the light box provides the back lighting.
The results have been really good, especially those which had been taken outside, but I think that's more a reflection of the slide than this technique.
I'm going to start digitising my more recent slides over the coming months and will try to post some results here.