It kinda depends...
See a cheapo place would probably use RG6, a wall wort and two baluns. That drops the price of result as much as possible. They might also use regular Cat5 inside conduit and run the power over it too. That would make $500 aside from the DVR very possible. However that would have to be completely reworked to add another camera.
I would want you to get direct burial Cat5 inside conduit, a UL listed power supply that would support the 8 channels you desire on the DVR in the end. I also factor in your current automation and security system and end goals there to ensure the DVR fit in with them as well. Also the "hybrid" factor basically kills all the really budget DVRs, many cheaper companies can't integrate IP cameras they don't sell/install. Some IP cams aren't very well supported outside of their own codec in their NVR software, so that needs to be taken into account too. I basically don't have anything for recording that can plug and play and meets all of our needs thats under $500 in itself.
Conduit is not required for direct burial, but if you use it you can later pull wire out there with ease, this would allow for speakers, a drieway monitor or whatever other LV you might be able to dream up. Size the conduit for this. Otherwise you can directly bury direct burial cable, you can use landscape lighting wire for the camera's power.
Realistically, and done so you don't need to swap stuff in the future I'd guess $1500-2000 is alot closer. However that would basically provide for a buch of expansion and integration you may not really need or want. That would also have enough wire and connectors to max out the DVR (or 1000' 95-110% copper RG59-18/2 siamese).
They don't say a picture is worth a thousand words for nothing, being able to see the driveway would help alot. If you PM me pics make sure and list make/model of the IP cams you already have.