A review of our 1st Digital Single Lens Reflex camera:
Canon 300D (circa 2003) bought used for $100

Features:
USB 1.1 (very slow in transferring images off via USB cable to computer)
CF memory card (very slow saving files, low capacity)
1.8″ rear display is small and fixed
6MP APS-C sensor
No live view on display
Video: No
RAW format Yes
ISO 1600 max

We have used it for astrophotography using 18-55mm for widefield night photography and a75-300 zoom lens with a 58mm solar filter for daytime solar photography.
It is not the greatest but can do 30sec exposures on Manual. In Bulb mode and with the intervalometer, much longer exposures can be made.