Well, cheapest solution would probably be your existing PDC (if you have one) plus a watch like say a Casio G Shock
I have an old analogue Citizen Aqualand which also shows depth but they're not easy to find these days (and cost more than a G Shock)
Or you could use a BT (e.g Uwatec 330) plus the watch, and dive on cut tables, which works great for square profile tech dives
I have an old analogue Citizen Aqualand which also shows depth but they're not easy to find these days (and cost more than a G Shock)
Or you could use a BT (e.g Uwatec 330) plus the watch, and dive on cut tables, which works great for square profile tech dives