The chain is a easy replacement and fairly inexpensive. Although you do have to size the chain you get to the correct length for that bike. You might could just size it to the same number of links as the chain on it now. But being a used bike in poor condition, then you don't really know if a previous owner replaced it sometime in the past and correctly sized it or not. And sizing a chain requires tools. Many people today don't have the skill set to just use a punch and hammer as we did BITD. I still today size a 11 speed chain with a punch and hammer. But can you? A good chain tool that won't bust on the first use will cost more than what the shop will charge to replace a chain. But if you don't ride that bike a heck of a lot of miles, you may never need that chain tool again if you buy one.

However just brushing off any surface rust with a wire brush and lubing the chain might get it functional again for a while. Tight links sometimes work themselves free after some use. Though they might also cause other issues for you during that time period it takes for them to free up.

You seem to say the front wheel can't be steered and that the headset is frozen up. Probably the bearings are rusted up. You'll have to replace them and hope that nothing worse is going on. Will you know what bearings set to get for that bike? The spacers you took off control not just how high the stem sits. But also they allow you to have the stem at the height you wish on the steerer tube, while maintaining the proper force on the bearings to keep your headset from being too loose or too tight.

And still, you haven't even begun to find out if the shifters and brakes work on the bike. That might require cable replacement and the pads. Or even the entire component if the previous owner mucked them up.

The tuition for DIY school isn't free. Most of your stuff can be fixed and adjusted. But you will probably pay a high cost for that bike to get it running. So consider the price the bike shop gave you. Or better, return the bike if you can get your money back. IMO, you can find a used bike in good working order for the amount you'll pay to DIY it back to working order.


This place has to good information and videos for helping you DIY all those things your bike will need. https://www.parktool.com/en-int/blog/repair-help