if you want to buy or use iPad as your laptop replacement you can do it . iPad Pro is good enough. You can trade in your old iPad with iPad Air it’s good enough and if you looking cheaper than it you can buy iPad 8 or 9th gen it’s cheap as enough 359$ . If are you trade in or you can visit apple education site and get discounts and trade in your old iPad .
iPad Air is so power ful to replace a Mac book air . (Watch all the images shown here)
additional info ; https://www.apple.com/us-hed/shop/buy-ipad/ipad-air , or iPad modules : https://www.apple.com/us-hed/shop