In the States, these are refered to as ECBs (El Cheapo Brinkmans) and can be had for $30-50.
The problems they have are lack of airflow control, the bottom is open with no way to control the airflow to the charcoal bowl; ash build-up, the charcoal bowl has no grate to keep the coals up out of the ash that develops. These problems are more noticeable when trying to BBQ at higher temperatures (225-250F).
These two problems make it hard to control the temperature. This can be overcome by controlling how many briquets are put in the smoker, as DarrinG has suggested. The ash problem can be helped by using lump charcoal rather than briquet charcoal. Lump creates far less ash.
For smoking at lower temps, once you figure out how many pieces of charcoal to put in to achieve the desired temp, it should be okay. The only problem would be adding charcoal on schedule to maintain the temp.
My salmon smoking takes six hours, some smoking takes longer. That's a lot of "baby-sitting" of the smoker.
Short answer: Work the hotplate modification to the above mentioned Brinkman, or find an electric smoker like
this one.
