You need to layout your actual requirements, is this indoor or outdoor? If outdoor burial or aerial? If indoor riser or plenum? bend insensitive required? What type of redundancy (diverse paths, etc). Single strand is really odd to be looking for as most SFPs are duplex (same frequency, transmit on one strand and receive on the other).

Single mode has allot of future proofing built in by its very nature. The same single mode fiber (OS2) can run anything from 1G up to 800G, potentially more if you use C/DWDM. Multimode keeps changing fiber types as the speeds change (they are up to OM5 now for 100G. The instant you go outdoors single mode is the way to go as the labor cost for digging up or re-lashing to a pole a new fiber to support the increased speeds will far and away outpace the cost savings by going multi-mode. Most outdoor single mode will come fully armored by default as it is expecting the harsh realities of the outside world, for indoor use these can actually be difficult to work with as the cable tends to be very stiff due to the strength member which can be a number of materials including fiberglass and steel (bend insensitive this stuff is not).

For working with fiber the core tools are available on amazon for less than $100 to get started (search for "ftth tool kit"):

• Fiber Stripper
• Cleaver
• Light pen
• Light meter
• Kevlar shears (special kind of scissors)
• Alcohol + lint free wipes (most kits will come with the container for the alcohol and you pick up the alcohol from a pharmacy).
• LC to SC adapter
• fiber cleaner for the ends (they will be typed to the kind of fiber connector you are using LC, SC, etc).

Nice to haves / you have specific requirements:

• OTDR - If your runs will be less than a km then skip this the light pen and meter will suffice for most of your needs. If you are buying then don't forget the launch cable to allow you to detect breaks close to where you are measuring.
• Splicer - Now you are playing with the big boys and I would recommend you get some training before you frustrate yourself.
• Fiber microscope - Highly unlikely you need this but helps view what is going on with a fiber most notably dust but can help with detecting cracks on the fiber face.

Without the other information can't really make more recommendations as most outdoor is terminated using pigtails or ends are mechanically spliced on (very few sit down and polishes ends and plays up with epoxy these days). Your light pen and meter will then be your best friends to confirm that you are indeed getting signal from one side to the other.

As for bulk fiber you will have to look around, price tends to go down with order quantity (I work for an ISP we order those rolls you see pulled behind trucks straight from China). For the indoor stuff you may want to check https://www.cablewholesale.com/products/bulk-cable/fiber-optic-bulk.php as they are the ones selling on amazon (cut out amazon and the price drops a bit, they also list quantity discounts). We haven't used them but the pricing looks good and they don't look to be a bad seller on amazon ( https://www.amazon.com/Fiber-Indoor-Outdoor-Optic-Multimode/dp/B0088L4PTK/ ). I have nothing to do with them as a disclaimer but I have been looking at them for an internal re-wiring we have been looking at (full leaf-spine data center deployment). You really only want to be doing custom runs for stuff between racks / rooms / buildings, within a rack just go to fs.com and pick up some patch cables of the appropriate length. Patch panels and couplers are your friends for indoor deployments especially with single mode you will almost always have light power budget to spare.

SFPs I like fs.com the price is really hard to beat and the reliability is up there, as with anything buy spares (I had a Cisco XFP10GLR-192SR-L fail today so don't assume paying more will automatically get you more quality, beyond a certain point it makes little difference). If you have a mixed environment then the FS-BOX allows you to dynamically re-flash a fs SFP to a different vendor (almost had to use that today).