The Packer Lodge provides basic but clean accommodation and excellent staff at basically the lowest prices you'll find in Jakarta. I stayed in the private single room. I was able to check in at like 2 AM with no hassle. Make sure to bring 200,000 IDR in CASH for the deposit.
The room was basic, but clean. AC had no trouble keeping the room cold. There was tons of storage including a lockable closet. Sink does not get hot water, and the shower has a small water heater that runs out of water very quickly. I basically had to shower at a trickle unless I wanted to go to the public bathroom intended for the people in dorms (so why did I pay extra for a private room then?!)
WiFi in the property sucks. I had basically no signal in either of two rooms I stayed in while I was there. Telkomsel, the largest cell network in the country, also barely reached the rooms. You'll have to go elsewhere or to the lounge on the third floor to do anything useful on phone/computer.
If you can get a cheaper booking by choosing not to get the "free breakfast' I would just save the money, even though the breakfast is cheap. Pretty meh and there are tons of warung nearby with delicious and cheap street food.
Laundry service is good. About half a load for $4, with 24-hour turnaround. Very cheap for non-DIY hotel laundry.
The biggest reason you should stay though is the staff. Super friendly and helpful, and speak good English. Thanks to Felice, Gab, Yani, Keisha, and Dina!