Various light box/light sources + DSLR set ups that give good results, but it you want a faster solution then would recommend the Plustek Optiscan range. I tried the Epson mentioned above and found it to be awful (had several dead lines on the light source)
I bought one to digitise a load of old film and slides. Didn't bother with the bundled software just used it straight from VueScan. My approach was to get a nice flat well exposed scan and then used a Lightroom plugin to develop them based on profile of the film chemistry they came from (forget the name of it, cost about 20 quid I think)
Once I was done I sold the scanner back on eBay for about 30 quid less than I paid for it 8 months earlier.
https://plustek.com/gbr/products/film-photo-scanners/opticfilm-8200i-se/