If you have a Garmin Edge 520, 705, 800, 810 or 1000 & Touring and you don't have maps; then you are wasting most of the value of your bike computer. I highly recommend that you purchase a micro SD card and spend 15 minutes to upload maps. It will open a whole new world. Save your phone battery for pictures, online bike fix instructions and the Uber for the third flat; there are cycling functions just better suited for your Garmin.
Step 1: Buy Micro SD card
These are almost everywhere Walmart, Pharmacies, Best Buy. I event saw one at a 
gas station (don't recommend buying there). A 32 GB SD card (which it plenty of space) will cost between $12 and $25 now (technology gets cheaper over time).
Step 2: Load maps onto your Micro SD Card
OK, this is where I cheat. The link below provides excellent instructions by Garmin model (provided by DC Rainmaker). There are basically 3 steps: Downloading maps, installing maps and enabling maps. You will need:
- a PC or Mac
- the cable that came with your Garmin
- Micro SD Card (see step 1)
- Garmin (yes I know one was obvious)
Make sure you follow the instructions for your model of Garmin. And yes I did say 15 minutes but give yourself a half hour. If you are not at all technically capable but know how to turn on your PC, take an hour.
Instructions to load maps on Garmin
Good Luck!