Whether this radio economically serves your purposes depends on what you'll be paying for it and on what else you'll need it to do.
The XTS3000 is no longer made, replaced by the XTS5000 (and XTS2500). Fortunately, it's compatible with batteries and most accessories for the XTS5000, which are readily available. The battery in a used XTS3000 is very likely at or near the end of its service life; expect a new one to cost about USD 125. You'll also need a charger.
The model I is the "basic" model. It has no display or keypad, and can be programmed for at most 48 channels (16 channels in each of three "zones" selected by the a-b-c switch). Model III radios can be programmed for hundreds of channels, with the zone selected via the keypad.
Keep in mind that you'll need to have it programmed, which you'll probably need to pay a shop to do for you (or get the programming software and cable yourself from Motorola, which will cost you a bit north of USD 500).
So is it worth it? What will this radio cost? You can pick up a used, working XTS5000 or XTS2500 model III with the "FPP" (Front Panel Programming) feature on ebay for USD 800-1300.