If you check the in the Browse Projects area (lower left this page) under the Home > Concrete, Home > Driveways, and Home > Hardscaping questions and answers, you will find a number of responses ddressing normal concrete, asphalt, stone, paver, and stamped concrete/asphalt issues and relative costs, including one or two in the past 2 months specifically addressing stamped versus unstamped concrete, and quite a few on paver and similar products for patios and walks.
In general numbers, and not necessarily true for all areas, depending on local concrete and oil prices, and with the very small areas you are talking about, likely the following order from cheapest to most expensive, NOT including removal of sod and topsoil and placing suitable subgrade, would would likely be about $1-2/SF additional to all below, depending on depth to suitable material:
1) crushed stone surfacing (3/4" minus roadway base fill material) - $0.75-1.50/SF
2) asphalt $3-6/SF
3) concrete, plain or one color (may be cheaper than asphalt in some areas, especially for this small a job) - $5-10/SF
4) large walkway pavers or daisy blocks - $7-13/SF
5) brick or small or interlocking pavers - $10-16/SF
6) stamped asphalt or concrete (for this small a job, likely only viable if commonly used in your area, so contractors have stamps in their equipment already) - $8-12/SF
7) natural regionally local stone like limestone, flagstone or slate slabs - $10-18/SF
8) multi-colored stamped concrete (every stamped "paver" or "brick" impression individually and uniquely colored (for this small a job, likely only viable if commonly used in your area, so contractors have stamps in their equipment already) - $14-18/SF
9) fancy stone like marble or granite - $18-30/SF
As you can see, there is a lot of overlap in pricing between the various options depending on contractor experience and preference for materials they will be working with, so you really have to look first at what effect you want (or a couple of options), then get bids from at least 3 contractors for the optional surfacxes to see what the prices are in your area. Also, since your job is very small, costs will vary between contractors, with smaller operators probably giving the best prices as this size job suits them best.
Basically, for low maintenance, asphalt and concrete are usually tops UNLESS you are likely to have tree roots growing in underneath,then hardest to repair root bulging. If you don't mind resetting a few pavers every few years, then they are cheapest as a rule (after plain crushed stone) and intruding roots can be cut out and paers reset easily, although weeds in the cracks can be an issue for some people, particularly those adverse to weed killer. If you have true winters, the desireability of concrete (including thin (<2" thick) concrete pavers and daisy blocks) drops off as harsh winters cause them to deteriorate faster from freeze-thaw action and ice melt.
Interlocking pavers, stamped surfaces, and interlocking pavers add more to the house value and look fancier.
I would emphatically recommend a minimum 3' wide walkway, both for ease of snow removal (if occurs in your area) and also for handicap accessibility issues when you sell the house. Also, the narrow 2' width makes for a restrictive work area, so a 3' might not cost much more than a 2' width as easier to work on and move materials on.
Also, be sure excavation and construction of walk and patio considers drainage, so water is not trapped near the house or ponded by it, and so the walkway does not become a flow path.
In case you don't realize it, this is a perfect size job for a do-it-yourselfer, if you are up for that - would cut about 2/3 off the cost.