I’ve pondered buying expensive sous vide equipment, but found I can get the job done quite well with appliances I already have that would cost under $100 —a good quality digital thermometer (ideally one with a probe on a wire) and an electric wok or skillet with an old fashioned analog temperature control.
The analog control is essential. A digital control with low-medium-high like is found in crock pots is not going to do it. The old fashioned dial control on your mom’s electric skillet —the one with that curious metal spike coming out of it — is the kind you need.
The magic of this technique is once you’ve brought your food to cooking temperature (say 145-50) using a precise digital thermometer, you should be able to get your cheap, simple analog control to maintain it at that temperature with accuracy that is plenty good enough for excellent results.
Equipment I use: Breville Gourmet Wok (about $70 if you shop around), and a CDN digital probe thermometer (about $30 —this is the best quality therm of its kind that I have found under $100). A CDN instant read (about $20) would also get the job done. The CDNs are extremely good for the price —precise and durable. I think you could do this with a cheap $30 electric skillet, but the Breville Wok is something I already own.