Let me start by reiterating that backpacking is not longer an expensive hobbie or sport.
Globalization has created a lot of competition among manufacturers, bringing the niche market to an affordable balance.
While you can shave a lot of weight going super ultralight, in some cases, the expense to save a few ounces becomes a major investment. (The ongoing joke is pack one less snicker bar)
So lets start with the big 3 (backpack, shelter and sleeping bag). These 3 elements, take the manority of the weight and is the biggest expense in any set up.
If you are going to be carrying a maximum load of 25lbs including food and water, a 30-35L capacity backpack should carry all your comfort.
The big 3
Backpack: klymit motion 35L 24oz
As John Abela stated is a super comfortable pack that can be trim by eliminatinating unnecessary straps.
You can find it for $70 at mossejaw.com
Tarp/tent: six moons designs scout 34oz
The trekking pole set up is quick and reliable, make sure to seam sealed twice for full rain protection. At $125 is hard to beat.
Sleeping bag quilt: aegismax quilt 32F 16oz
The Japanese manufacturer has created a big buzz among ultralighters, with 850 fill of goose down.
Their quilt is almost an exact replica to Enlighment Equipment Revelation quilt.
You can find it in Alibaba.com for $86
Sleeping pad: klymit static v lite 2 $35 (refurbished)
Their pads are extraordinary for the money and their ebay front store carries refurbished or return items for super cheap. Weight 16oz.
Pillow: klymit cush 2.5oz $15
In our opinnion is hard to beat an item that can be used as 2 different items.
The cush can be folded and used as a seating pad.
Stakes: vargo titanium sheppard hooks (rugged, durable, ultralight and can be used in any terrain)
Set of 6 $25 weight: 1.75oz
Total sleep system cost: $370
Total sleep system weight: 70.25oz
Toaks titanium 550mm $25 weight: 3oz
Brs 3000 stove: 0.5oz $13 via amazon.com
Sea to summit alloy long spoon 1oz $10
Gsi ultralight java drip 2oz $10 (grind your coffee super fine so you dont need a filter)
Sea to summit collapsible cup 2oz $10
Lightload packable towels: for all cleaning purposes $2 ea. 1oz
Cooking sytem cost: $70
Cooking system weight: 9.5oz
Adventure medical kit solo $14
weight: 10.4oz (can be trim or added depending location and distance)
Anker battery bank 10000mAH $25 weight 9oz (charges your phone from 20% to 100% 6 times)
Compass/temperature thermometer: silva 2oz $10
Miscellaneous cost: $49
Miscellaneous weight: 21.5oz
Water and filtration:
sawyer squeeze filter 3oz $30
2 smart water bottles 1L 2.5oz $5
Total cost: $524
Total weight: 107oz/ 6lb 11oz.
While we couldnt accomplish an entire list for $500…we got damn close.
Final note: as baseweight we did not include trekking poles, food, water, fuel or clothing.
Clothinwise: hit your local thrift shop, you can score high quality gear depending your location for dirt cheap.
Regarding trekking poles: cascade technologies are a great inexpensive option. Their cork handle flick locks built a good reputation among hikers. Available for $49.
Enjoy the pack list and if you go out, stay safe and if you are new to the sport always check with somebody more experienced about your needs.