If that's a Biostar M6TLC, not very much.
Intel 440LX---I believe the first chipset for P-II/Celeron
* Intel Pentium II
* Celeron Processor up to 500 MHz
* Slot 1 Processor support
* Intel 440LX
* Three 168-pin DIMM Sockets
* Supports SDRAM/EDO (3.3V)
* Up to 768MB Memory
* 3 x ISA Slots
* 4 x PCI Slots
* 1 x AGP Slot
* 2 x Ultra DMA/33 Bus Master IDE ports
* 2 x USB ports on board
* PS/2 Mouse & Keyboard Connectors
* 1 x FDD, 2 x Serial Ports, 1 x Parallel
* IrDA Support
* ATX Form Factor
* Dimension: 30.5cm x 19.0cm (W x L)
DMA/33---OK for older systems like this, but pretty slow.
Celeron 300---Better then a Pentium, I guess.
No more than $20 for the mainboard, $20 for the CPU and $15 for the RAM.
If I had the cash, I'd probably take it from you for $65...possibly up to $80.