Try quiches from the supermarkets. You can buy 3 for £10 in Marks & Spencer and cut them into 8 slices. I think this is easier than making your own by the time you have bought pastry, eggs, cheese and bacon etc.
You can make your own sausage rolls with bought puff pastry and taking the skins off nice sausages for the sausage meat filling. They are not hard and you can make a big plateful from one pack of pastry and a pack of 8 sausages if you cut them small.
Make your own potato wedges, par boil them first and roast in oil with salt and pepper in the oven. Or jacket potatoes in the oven. I have even roasted those tiny new potatoes in oil in the oven in their skins and they were really lush. And cheap! My friend makes her own potato salad and it is better than shop bought.
A big bowl of fresh pasta spirals with stir through tomato/pepper sauce goes a long way and is really cheap. You can add some flourishes like sliced peppers and olives so it looks home made. It really takes seconds to knock up but looks like you have made a massive effort.
Pizza sliced up and piled high always goes down well. Supermarket (I like Tesco's one) own brand thin sliced pepperoni or plain cheese is good and cheap.
I buy the pre prepared salad bowls for my spreads as I think they are cheaper than buying the salad leaves, toms, cucumber, peppers, etc separately. I normally get away with a £2/£3 salad bowl for 10 people as you don't need as much as you think. I make my own dressing with cider vinegar, honey, olive oil and grain mustard.
Home made garlic bread is always popular but hard to keep warm.
If I am feeling rich I do some racks of ribs or chicken breasts for the carnivores but I find people just love the finger foods and nibbles best.