How much ???

since your accord is an older model you don't have the security stuff, if u had alot of time on your hands, knew how to work a DMM, Relay, and diodes. you may be able to do it yourself. here is the wiring diagram for your vehicle

|       ITEM      |     WIRE COLOR     |POL|       WIRE LOCATION        |
|              12V|white               |+  |ignition harness            |
|          STARTER|black/white         |+  |ignition harness            |
|         IGNITION|black/yellow        |+  |ignition harness            |
|        ACCESSORY|yellow              |+  |ignition harness            |
|       POWER LOCK|black/white *1      |-  |lower drivers kick *2       |
|     POWER UNLOCK|black/red *1        |-  |lower drivers kick *2       |
| PARKING LIGHTS +|red/black           |   |fuse box in dr. kick        |
|       HEADLIGHTS|blue/red or blue    |-  |steering column             |
|     DOOR TRIGGER|black/white         |-  |brown plug left of column   |
|  TRUNK/HATCH PIN|green/black         |-  |green plug left of column   |
|         HOOD PIN|                    |   |                            |
|TRNK/HTCH RELEASE|                    |   |                            |
|  FCTRY ALARM ARM|                    |   |                            |
|FCTRY ALRM DISARM|                    |   |                            |
|       TACHOMETER|blue                |   |distributor                 |
|       BRAKE WIRE|green/white         |+  |at brake switch             |
|     HORN TRIGGER|lt. green/blue *3   |-  |column or horn relay        |
|           WIPERS|                    |   |                            |
|  LF WINDOW UP/DN|red/yel - red/blue  |A  |drivers door switch         |
|  RF WINDOW UP/DN|blu/grn - blu/yel   |A  |in drivers door or dkp      |
|  LR WINDOW UP/DN|green - grn/yel     |A  |in drivers door or dkp      |
|  RR WINDOW UP/DN|yel/grn - yellow    |A  |in drivers door or dkp      |


Notes:
*1 The station wagon uses green/white for lock and yellow/white for unlock.  These wires are found either in the drivers door harness or under the rear seat.  
*2 Locate the large harness in the lower below the carpet in the drivers kick panel.  Near the foot rest you will notice a piece of blue tape attached to the harness itself.  Reach around to the underside of the blue tape to locate a 2 pin gray plug with the lock and unlock wires attached to the plug.   
*3 High-current ground.  Use a relay when interfacing with this circuit.

EIDIT: hondaman-iac tried to make the code fit in the page