When I play a Long Sword or a Sterak's Gage, can I attach it to a unit for free? Or do I have to recycle 1?

Free on the initial play — no recycle needed.

Both Long Sword and Sterak's Gage have Quick-Draw (Rule 819): "When you play this, attach it to a Unit you control." That triggered ability attaches the gear for free as part of playing it — you only pay the printed Energy/Power cost. The [C] Equip cost (Recycle 1) is only used later, if the gear becomes unattached and you want to reattach it via the normal Equip activated ability (Rule 818).

One note: if you control at least one unit, the Quick-Draw attach is mandatory — you can't play the gear and leave it sitting unattached at your Base.