Research the specs on the laptop and determine the size and model of the largest memory-kit available. If there are empty slots, determine the cost and size of using them with another module or another kit.
Then, use the information as a selling point, provide the information about resellers for purchase, and cut it loose for whatever you can get for it.
Looking at the specs for that model and a similar HP, I see it's about the same generation as my own laptop. I never bought a new laptop. Mine is an old Gateway E475M "executive" dual-core Celeron/Centrino. For most conventional office tasks it is perfectly adequate -- and I can even watch TV on it from my Silicon Dust Ethernet tuners wirelessly -- until someone flips on the microwave.
I think I upgraded the "G" wireless Intel NIC to an "N" which cost me about $10. I connected a 500GB MX100 SSD to the Gateway's SATA II controller, and discovered almost by accident* that it would handle a 2x4GB Crucial SO-DIMM kit rated at a higher speed than would be selectable in BIOS, so it runs at DDR2 666.
I couldn't probably get a dime for it, then maybe someone might give me something. On the other hand, I can postpone buying a pricier current-gen model -- probably for even a few more years.
* The documentation for the E475M was ambiguous. It made one think that the limit was 4GB, and should have been specific that this meant "per module." I was lucky to figure it out.