$100 is considered a budget price, but you can still get a lot of choices for smartphones under this range. So, if you're looking for a phone under $100, here are some recommendations:
1. Xiaomi Redmi 6A: the best phone under $100
Price: $99

Listed as one of the best phones under $100 on the market today, the Xiaomi Redmi 6A offers users a modern design and numerous advanced features.
Featuring a large 5.45-inch HD+ display, this phone is powered by the Mediatek MT6761 chip paired with 2GB of RAM, handling everyday apps and mobile games smoothly. It also supports dual SIM, along with a 3000mAh battery, meeting users' needs for all-day usage.
Xiaomi Redmi 6A excels in photography with its 13MP main camera and 5MP front camera, allowing users to capture life's moments with clarity.
2. Xiaomi Redmi Go: Xiaomi's cheapest phone under $100
Price: $49

As Xiaomi's most affordable smartphone to date, the Redmi Go offers users a solid smartphone experience with its 5-inch HD display.
Powered by the Qualcomm Snapdragon 425 chip with 1GB of RAM and 8GB or 16GB of storage, this configuration is basic, suitable for users who primarily use their phones for calls and messaging.
Nevertheless, this affordable phone under $100 is also equipped with an 8MP primary camera along with a 5MP selfie camera, meeting basic needs for photography and video recording.
3. Nokia 3.1 16GB
Price: $99

Nokia has always been a brand associated with inexpensive and durable products, and the Nokia 3.1 doesn't disappoint.
Featuring a 5.2-inch HD+ IPS LCD display, the product also boasts a fairly decent configuration for its price range with the MediaTek MT6750N chip paired with 3GB of RAM and options for 16GB or 32GB of internal storage.
Nokia 3.1 also delivers good photography capabilities in the sub-$100 phone segment with a 13MP primary camera and an 8MP selfie camera. The 2990mAh battery also ensures long-lasting usage for users.
4. Samsung Galaxy J2 Core
Price: $99

Listed among Samsung's budget smartphones released in 2018, the Galaxy J2 Core offers users a standard smartphone design with a 5-inch display and a slightly subpar qHD resolution.
The J2 Core is equipped with the budget Snapdragon 425 chip paired with 1GB of RAM and options for 8GB or 16GB of storage, meeting very basic user needs and struggling with installing heavier apps and games.
Samsung's sub-$100 phone is also equipped with an 8MP primary camera and a 5MP selfie camera, offering mediocre photo quality. However, the 2600mAh battery can reliably last all day for users without worrying about running out of power.
5. Nokia 2.1: Nokia's budget phone under $100

As part of the revitalization plan for the Nokia brand, Nokia 2.1 brings users a modern, affordable smartphone. Sporting a 5.5-inch HD display and a massive 4000mAh battery, it's one of the most affordable big battery phones on the market today.
However, the device's specs are basic, featuring the Snapdragon 425 chip paired with 1GB of RAM and 8GB of internal storage. The cameras are also unimpressive with an 8MP primary camera and a 5MP front camera.
Bottom line: for phones under $100, users can only expect basic features, suitable for everyday calling or as a backup phone. At this price range, it's also challenging to find a phone with a large battery capacity.