That depends on how far and what other purposes you want it for. Fuel needs are the biggest issue since we won't be able to recharge or replenish. That means you need to build something carrying its weight plus that of whatever equipment you want on it. The less equipment we need, the easier it'll be to get the energy required. We could try building somethin' with solar components in the manner of Mars probes, but that has particular costs and only works if we're sendin' it somewhere to get enough sunlight.

Transmission should be the easy part, but if somehow we're goin' somewhere out of range of the kind of transmission tech we have access to, we'd have to design it to set up its own relays as it goes along.